Hi, I'm 32 and a UK size 6-8. I used to be a 10, I haven't changed but I think vanity sizing has a lot to answer for! I have Top Shop stuff in my wardrobe bought years ago with a 10 label that is the same size as size 6 stuff now. Anyway, I digress.
Favourite shops are:
Oasis, Warehouse, Uniqlo, H&M, M&S, Dorothy Perkins, Gap, Benetton.
I used to love Next about ten years ago but never go there now - not even for DD's stuff. I just think the quality has gone - completely.
I am living in the US right now and have really struggled to find things small enough here - currently 16 weeks pregnant and still fit into a pair of supposedly size 0 shorts. These are honestly more like a UK 12. It gets really annoying after a time and I end up buying lots of Oasis and Warehouse online and having it shipped over. In fact, there's one great website where stuff is half the price of the UK but turns up with the full UK £ price tags on.
Underwear is a mix of M&S - boring everyday (all the British expats I know stock up when they're home), Calvin Klein - nice stuff, bargains to be had stateside and Bravado seamless silk feeding bras - post DD and now going into second pregnancy. Interestingly, it's cheaper to buy these in the UK.
Can anyone tell I spend way too much time comparing the best deals by country?!