I've got one of those Airbike P7 lights On-One were doing last year and, like a few people, I'm not a fan of the supplied clamp. I know that there were a couple of clamp replacement options available and a quick search on here throws up a [url= http://www.lumicycle.com/product/5/qr_cam/qr-camlock-bracket.html ]Lumicycle[/url] option but I'm sure that someone suggested a cheaper option that was available on CRC; I'm not sure which it was (or even if it's still available) so if anyone can point me in the right direction I'd be grateful.
I used one of these. I got the double because the single wasn't (and isn't) available.
http://www.chainreactioncycles.com/Models.aspx?ModelID=12871
I needed to enlarge the hole slightly but that was easy. You can either dril or just use something hot (skewer+ hob or soldering iron).
Had mine set up in this way since last year when I bought it and it's been fine.