I've no idea.
Probably about 2K or more... though a lot more if you include people I've sent to them. For example, my work just got 700 pounds worth of PC bits from ocuk delivered today. Before that, 300 or so, a few friends maybe about 600 each....
I've probably directly or indirectly given them about 5 - 6K.
*EDIT*
I also straight told them (people I've advised) forget it if the other store is a bit cheaper. Don't risk it, OCUK you're going to get good service, and what you need, and not be fobbed off with trash or excuses.