Try the Deliciously Ella feel better app for recipes and her books generally - even get them from the library. You'll get loads of meal ideas from that, and mostly whole foods (and genuinely delicious).
Here are some pointers in terms of dairy, though if you mostly eat whole foods, you may find you can live without all this, or at least the majority of the time.
CHEESE
Forget trying to get the exact taste - it won't happen, so you just need to find an alternative that tastes acceptably different. If possible, cut cheese out altogether for a while before trying the vegan ones, so your brain has a chance to forget it a bit and you're not doing a like-for-like comparison!
Plant-based Cathedral City has still smells like vegan cheese when you open the packet but it tastes better than all the other mass-produced vegan cheeses. You can get it in Tesco, Sainsburys and some others I think. Ilchester vegan cheese block is widely available and although not as good as Cathedral City, mixed with some cream cheese and seasoning, it can make quite a nice macaroni cheese. A lot of people love the Applewood Smoked vegan cheese, but watch out, as it's sometimes next to the non-vegan Applewood cheese so it's easy to pick up the wrong one!
Otherwise, nut-based cheeses are best but you mainly need to order them online and they're very expensive, small batch affairs - good if you want a very realistic cheese board for a special meal or something but usually too expensive to be buying every week!
For cream cheese, plant based Philadelphia is a 90% replica of Philadelphia, I'd say. It's made with almond and oat milk, rather than coconut oil like the other ones are. Nush cream cheese is also delicious and you can get it in some Sainsbury's, Morrisons or Waitrose but it's not stocked in my local ones anymore.
Violife Le Rond camembert is supposed to be good, but I was never a camembert fan so I can't vouch for it myself!
Vegan Babybel is available in some bigger supermarkets, mainly Sainsbury's and I think Asda. I kind of like them - they're not really like Babybel but something closer to a solid Dairylea, but still just good for something different to throw in a picnic or my daughter's packed lunch.
MILK
For coffee and hot chocolate (and cereal if you like a more "whole milk" taste): Oatly Barista. It's a grey carton in the long-life section of pretty much any supermarket and Co-op. The one in the fridge tastes different. It's great if you use a milk frother for coffee - no other milk compares in my opinion. I now order it on subscription from Amazon.
For tea, I hear Alpro My Cuppa is very good (most people don't like oat milk in tea, though my husband doesn't mind it)! Soy milk is supposedly nice in tea, but I'm just not a tea drinker.
BUTTER
To replace butter, there are loads of spreads (most of the Floras, Pure, Vitalite, etc.) but I like a more buttery one and like it not to come in plastic, so I use either Flora Plant blocks (the salted one for toast and sandwiches and the unsalted for baking) or Naturli vegan block. Both are in the majority of supermarkets these days and they taste really nice!
YOGHURT
Alpro do some really lovely individual yoghurts now in various fruit flavours. There is loads of choice in terms of big yoghurt tubs but less in individual ones, though Morrisons do their own brand individual pots (I think I had mango), Tesco brought out individual fromage frais are lovely, and Petit Filous just launched dairy-free products, too.
SNACKS
Tesco do nice chocolate digestives - Tesco's own dark chocolate ones are about 60p and they don't taste properly dark and bitter - more like a cross between milk and plain chocolate. Oreos are dairy free, as are most own brand bourbon creams. Morrisons do some lovely Free From cookies. Rhythm 108 chocolate cookies are addictive. Tesco Wicked Kitchen (fresh) double chocolate cookies are good.
For chocolate, if you like dark chocolate there's more choice, but for milk chocolate you'll mainly need the Free From aisle. A brand called Buttermilk (ironically) does good dairy-free bars that are like Crunchies, some a bit like Mars bars (not a replica but that sort of nougat), and a peanut one (again not exactly a Snickers but still nice). If you really like Snickers, there's a brand called Jokerz that does a great replica but they're made in America so not cheap. I like Rhythm 108 chocolate bars (all flavours), Vego bars and Co-OP's own (Gro range) chocolate is hazelnutty chocolate (think Nutella) and amazing for only about £1 for a big bar! Co-op also have fantastic chocolate orange buttons,. Morrisons also do a a slightly darker orange chocolate bar in the Free From section that's nice. The dairy-free Dairy Milk and Lindt bars are ok but I got so excited thinking they'd be accurate replicas - they're not, but try them anyway, you might like them. NOMO is a good brand too - I like the fruit crunch one best and my husband loves the caramel (and he's not strictly dairy free but also eats pretty much everything I'm listing here). Love Raw are a great brand who do a wafer bar that's just like a Bueno! It's sold in some supermarkets plus Holland and Barrett.
Crisps often contain milk powder, so watch out - even ones you wouldn't expect. I like spicy ones and luckily Doritos Chilli Heatwave, Wotsits Flamin Hot and Niknaks nice n spicy are all ok!
There are a variety of nice chocolate spreads, but my favourite has to be Vego. It's in some supermarkets, Holland and Barrett, and I've seen it in quite a few independent food/refill shops so I think it's quite popular.
Soreen are all vegan, as are Deliciously Ella cereal bars, and Naked fruit and nut bars.
CREAM/CUSTARD
Both Alpro and Oatly make nice custard and cream. Heavenly Whipped by Food Heaven (black tin) is great for squirty cream! It's in most supermarkets too. I have it on hot chocolate.
DRINKS
For hot chocolate, always check the label but in general, most instant (add hot water) ones contain milk powder (except the specific vegan Galaxy one and vegan Options), and most that you add milk to are essentially cocoa powder and sugar so you can add whatever milk you like - Dairy Milk, Twinings, etc. - the choice is yours.
If you like a hot malted drink, Horlicks do a vegan one, though I wish Ovaltine would do a vegan one as I prefer that.
Rebel Kitchen sell small ("mylk") milkshakes - I tried a banana one, found in a Waitrose, and it was very nice! Alpro also do small cartons of strawberry soy milk. There are a few larger cartons of chocolate milk to buy as well. Chocomel is a good one.
ICE CREAM/ICE LOLLIES
Vegan Magnums are highly accurate and very nice. We also love Sainsbury's own Cloudy Apple ice lollies which are 100% apple juice, and I think the orange ones we get are Del Monte. Coconutters do great chocolatey coconut ice lollies, too.
There are so many ice creams to choose from now and I think it's a matter of which flavours you prefer. Vegan Ben and Jerry's have mostly been good, I think Oatly ice cream was pretty good. My husband liked the Co-op's own salted caramel one and the vanilla Swedish Glace (which is available in a lot of cafes and ice cream places these days).
CAKES AND DESSERTS
Own brand (e.g. Tesco) frozen apple strudel is usually dairy free. There are some great frozen Deliciously Ella desserts, too. Some own-brand jam/custard doughnuts (Morrison's I'm sure, and possibly others) are both dairy and egg-free.
The Coconut Collaborative little chocolate pots in the chilled section are very nice.
M&S did a great vegan cheesecake (it comes in a pack with two portions), not sure if they still do.
Just Love Food vegan chocolate cake is good as a birthday cake - family commented that they'd never have known it was vegan. It's definitely in Tesco and Sainsbury's - maybe other places, too.
EASY MEALS
Goodfellas vegan pizzas are nice - I like the spicy vegetable salsa one and chick'nless supreme. The Chicago Town stuffed vegan sticky barbecue jackfruit is one of my favourites, though. Kirsty's brand do a nice Mediterranean flatbread pizza and a frozen vegan lasagne. Cosmo's vegan vegetable pizza was quite good, as is the Dr Oetker Ristorante tomato and pesto one.
Dominos and Papa John's both do takeaway pizza with vegan cheese, and Subway has the option of vegan cheese. Pizza Express do amazing vegan pizzas!
I recently got Morrison's Plant Revolution creamy tomato and herb pasta sauce and can recommend it!
Tesco Plant Chef do some really, really nice tins of soup, and they're only about 45p or something like that. I always keep a stock of them for quick lunches and my whole family love all the flavours. DD asks for her "favourite soup" which is the Plant Chef red pepper and lentil one. I think she likes it more than my homemade soups!
Jus-Rol pastries are dairy free, or the ones I've bought from the range are. I sometimes get puff pastry, roll it out and throw toppings on to make a sort of vegetable tart for dinner. The croissants, pain au chocolat and cinnamon rolls are all safe, too, and quite fun to make with little ones.
Like the pastry, I sometimes also either buy or make a pizza base so you can make your own pizza with whatever toppings you like, either with vegan cheese or with loads of sauce and toppings but no cheese.
Oatly creme fraiche is nice with fajitas.
Sacla vegan pesto is nice (especially the tomato one).
RECIPES
For recipe substitutions, you can use whatever vegan butter/milk/cheese you've chosen. Make sure you use vegan stock cubes and gravy and things like that (widely available).