Bleurgh - whatever you do, don't buy Pampers. I do cloth as well, but have disposables on hand for travelling. Pampers smell! Not poo-stinky, but artificial baby poweder-ish weirdness that gets stronger as they get wetter. Way weird if you're used to cloth.
There are a couple of Whole Foods Markets in the UK that can help you out - a few in London, one in Glasgow, and others opening all the time.