This might be a long one although I'm not sure how helpful it will be. I really struggle with dresses. I don't have a specific shop I go to and so I grab suitable looking dresses when I see them and if I can justify the purchase. Evening/occasion dresses are not too difficult if they're long or fit and flare. Hobbs are good but I haven't bought a dress there in ages. ASOS is good for jersey maxi dresses in spring/summer - variations on the goddess style.
I have bought a few vintage dresses from Etsy (you can find reasonably priced stuff but factor in postage and customs charges from the USA based shops).
Generally I find I have to stick to the fit and flare shape so it fits my top half. For summer I tend to wear either a 50's style sundress or a slightly floaty 70's style, knee length, midi or maxi (which I love as I don't love my knees or my chunky calves - but that's another story!).
For winter I don't really wear dresses unless it's for an evening do or if I wear one for work once again its a fit and (gentle) flare or A line.
It's not that I wouldn't wear a dress that's fitted on the bottom half, but I just cannot get into them. The only exceptions were a vest like jersey dress from a range that Denise Van Outen did for Very but that was back in 2007 and it was a maternity range so more generous round the tummy and arse and an ASOS midi dress with a tulip style skirt which I had to buy in a size 10 and have altered.
With those caveats I would also recommend:
Bernie Dexter. Full on 50's style. This is the USA site but if you search around you can get them online here. Great for a summer dress but the waist does come up small so you may want to size up.
& Other Stories. A bit random IMO and I don't shop there that much. In summer they tend to have light, silky dresses which flare a bit and are a little bit looser on top but not too floaty. Nothing there that really does it for me right now, but worth a look.
Etsy
Vintage and mostly American. Ranges from high end designer pieces with prices to match, to some good bargains. Approach with the usual caution about vintage and check photos and measurements carefully. If you don't like wearing vintage it's still great for ideas. Amazing how much high street stuff (like that M&S suede skirt) is a direct copy of a vintage item.
Over the years I have bought these and there's lots of similar stuff:
Off the shoulder tiered sundress. A bit boho but it was cheap and nice - loads more like this on Etsy.
Maxi "hostess" dress with leopard print.
Beach dress. This shop is in Thailand. It's all polyester but good for holidays/packing, quite reasonable and they will do simple alterations to length and width. They came up quite big on me and I needed tit tape on the strapless dress. It's called Onumadress.
A 70's disco dress - my favourite Etsy purchase.
Discoleafvintage on Etsy has quite a bit of 70's stuff. Good for ideas but a bit too pricey for my liking. They have a sale on at the moment.
Phew, sorry OP didn't mean to hijack
. It's just so nice to swap tips with other pears. Don't get me started on jeans...