Hi Lynne, I'm LCing in England too and am also insulin resistant, heading for type II diabetes.
We have our own forum (UK) if you look down the lists when the Forum home page comes on and it covers lots of these issues - weights and measures, sources of stuff, what the American names for things mean.
You can buy Splenda by mail order from Carbolow, an English company, it has a website, www.carbolow.com. They have a £5 postage charge, so you might as well buy lots of other goodies while you're at it!
Protein powder can be bought from healthfood shops in various flavours, body builders use it, though read the label very carefully - some are straight protein, others have very high carbs too as they're used for weight gain!
There are some excellent recipe sections in the Forum, again look down the list to find them - especially look out anything by Karen.
Wishing you all the best. BTW are you keeping a journal? Take care, Jay