Jess, try the following stores websites:

Argos(everything and then some is available from the website, problem is they may require someone to sign for delivery)

Habitat (furnishings ect)

Debenhams (same as habitat I believe the same company)

Rosebys (google them, their main website for the uk is under construction atm (upgrade work) they don't do many stores these days but heck they're on amazon)

Currys, Dixonsor Comet(these 3 stores are all owned by the same people, in fact so is PC world! they're probably the best electrical outlets in the uk for stuff like stereo's and stuff)

Other advice. Something Ewa found in Poland before comming to the UK, she has a multi-adaptor which converts her EU plug (2 round pins, earth pin is on wall socket) to UK plug (3 square pins, earth on plug) and has space for like 6+ items to plug in really damn useful since if you bring like hairstraighteners ect you'll need them. Don't bother trying to get US - UK adaptors in the UK, thats really hard to find we tend not to sell them in many places you could find yourself hunting around.

Also you can get some things from pretty much most supermarkets including Sainsbury's, Tesco and Asda they'll vary a little on price but I will with good knowledge on the matter tell you they buy all their stock from B&Q and Argos factories anyhow, I would know I used to deal with homewares in a supermarket.

If you need any more info or help pm/msn/usernote me