In reply to Leon_JF:
Maybe you're loaded but I don't reckon I would buy more than one set to start with. Buy one set, use them a bunch. See how you get on with them and which sizes you use the most before you buy any more.
I rarely double up on cams. I've only ever owned a single set myself but I'd often have the option of doubling up from partner's racks and it doesn't seem necessary very often. Most UK climbs suit a range of different sizes, you see relatively few near-parallel splitter cracks with no other options, unless you're specifically seeking them out.
I'm sure somebody uses offset cams in the UK but I've only ever seen them hanging in outdoor shops looking quite dusty. They're certainly not a starting-out item.
Personally, I reckon a set of Dragon cams would be a perfect place to start. Though I'm sure someone will pop in to say they're useless without thumb loops.