Cassandra, I am a Brit who used to live in the US, so I can answer the veggies thing. Your stuff tends to have to travel much greater distances and is routinely irradiated. This doesn't seem to be common knowledge over there, although it was a New Englander told me. In the US most apples are covered in wax as well. That's not something Europeans generally accept, so our food is more perishable. (on the plus side it's also much fresher and we can get organic food easily which I couldn't in the US!)
We don't have stuff like high altitude flour - and cornflour is a very different thing in the UK to the US! You can find loads of good cook books in any supermarket really - most 'tv chefs' have something or other out. Delia Smith is probably one of the most respected British cooks, and I think she has a very active website, but I've never been there! Also look out for Anthony Worrall Thompson as he does a lot of Low GI stuff.
http://www.deliaonline.com/
You measure in cups, and we use grams (or people my age still use pounds and ounces!) 25g is close-ish to 1 oz, so that's my rough and ready guide. All you need to follow a UK recipe is a cheap pair of scales. I remember being equally stumped by cups as who knows how big any cup is, but I just bought measures in the end! You will also find a bewildering range of cooking oils etc here, than in the US - also infinitely more wine, etc. Just experiment and find out what you like! So if you want to make a healthier roast, you can find a low GI oil like rapeseed, or use one of those flavour-less olive oils if you want the health benefits of olive without the taste. Or a load of other choices! Just have fun experimenting!
I'd check out the sugar content on them Nutrigrains - you'd prob be better off with a Mars Bar! (Ditto the Actimels).
I noticed in the US you also have a lot of those top loading washing machines which we haven't had since the 70s here! I never understand the laundry marks either and I grew up with them - just do everything at 30 or 40 degrees works for me! My machine has a 'delicates' option on the dial, that's what you need for silks.
The milk is different here too, eh? I remember you have percentages. Here, the lowest fat is the red top, then the green top. Blue top is full cream milk, the fattiest although actually it's still a low fat food so I'd just have whichever one you like and stick with it!
As for expense, have you discovered farmers' markets yet? I stopped using big supermarkets now and only shop at a small ethical one; and buy everything else on the market, meat from butcher, fish from fishmonger and we found we spend less as you don't impulse buy like in Tescos!