Straight away -
"TV, Broadband and Phones £100"
Wtf! What is the breakdown there? I'm guessing with sky or virgin? If so when can you leave them? They are extortionate and don't even provide a great service
"BT Broadband and landline is £29.99" that's ridiculous!
If you went "back to basics" you could easily do:
£12 tv licence
£16 broadband
£15 2 phones sim only contracts
Total £43
Even if you added Netflix 2 screens that's only another £8.99 - why are you paying £9.99?
"I own my phone outright as it was a Birthday present."
"My phone is £13" for sim only? With who?
When does his contract end?
Going deeper
Electric, Gas, Water, Council Tax £278
Again need a proper breakdown, are you with cheapest suppliers?
Water - is that based on usage and if so can you reduce usage?
Gas & electric - again check your usage, does the house really need to be that warm, even when you're not home? Most homes are well insulated now so cope fine with heating going off about an hour before you usually leave, are you in appropriate clothes for the season or overheating the house and lounging about in t-shirts? Electric cooker? Cook double, reheating the same meal another day in the micro can reduce costs, there are also meals you can cook entirely in micro. Have you a slow cooker? Much cheaper to use than an oven and can be used for loads. Are you switching devices OFF rather than leaving on standby or even worse leaving on when not in use? Ditto lights. Do you really need hot water ready to go ALL the time? Even when you're out?
"Food £500"
What "level" are you shopping at, are you a brand fan? Most people can manage to go a "level" down without a noticeable difference in most products. Even if you don't do it for all products it could still make a significant saving for you.
"food bill includes pet essentials, cleaning and laundry products, and nappies." These are very rarely cheapest at the supermarket especially the big name supermarkets. Do you shop around? I don't know about pet stuff but certainly cleaning and laundry products & toiletries are cheaper at places like wilko, pound shops, home bargains, B&M and similar.
Nappies again I'm not particularly familiar but my friends with babies tend to buy from Aldi/lidl or in bulk from Amazon or Costco.
So if you're saving on non-food items you'd be able to still have the food you like.
"Fuel £250" this is so dependent on region, cars, usage etc but on money saving expert there's a LOT on reducing fuel consumption by changing driving style, ensuring good car maintenance etc there are also apps and websites that tell you which of your local petrol stations are cheapest that week, we've a local Facebook page someone updates this on weekly.
Have you loyalty cards for everywhere you shop that does them? (Particularly useful for Christmas/birthdays)
"And we pay £25 to an ex gas and Alex provider from our old house" need to know more about this.