There's some overpriced, tasteless stuff out there, so here are some of the things I can't do without and stuff I'd recommend...
And for those of you who are visual - here's my pinterest pinboard of brand foods and some recipes I've found: http://pinterest.com/savvymamauk/gluten-free-dairy-free-oat-free/
HFS = Health Food Shops
Stock Cupboard Essentials
Kallo stock cubes
Dove's GF Plain Flour Mix
Granovita Yeast/Mushroom Pate (Asda/HFS)
Salute Rice Pasta (sold by Ocado - it really is the best GF pasta)
Granovita Brown rice pasta (HFS)
Sunita Pesto genovese (cheese-free) (HFS)
Sacla freefrom pesto (tesco)
Alpro UHT Soya Milk + Calcium) Potato doves potato Starch/flour* (morrisons/tesco)
*Potato Flour is the best thing I've found to thicken sauces and gravy. It's used in Chinese cooking lots. Just mix a couple of teaspoons in a cup and mix with a little water, then mix stir into your sauce and heat to thicken.
Dietry Specials rice/corn crackers
Kallo rice cakes
Koko coconut milk (very mild flavour)
Helmans original mayo (contains egg but not milk)
Seabrooks Crinkle cut Plain
Nakd fruit+nut bars ( not the oaty bars)
Calippo ice lolly tubes
Many brand chocolates are gluten free like cadbury's and Thorntons (check CoeliacUK food directory) but not milk free. Many of the GF sweets are also milk free though:
Haribo - star mix, strawberries...lots so check the CoeliacUK directory.
SwizzelMatlow - drumsticks, parmaviolets, lollies, love hearts, ...
Many Tesco, Sainsbury's and Morrisons own brand sweets too (see Cuk directory).