Seeing as there's just the one of him and he's standing next to an american (are those ANA in the background?) I'd hazard a guess that he's attached to the Spams in some capacity and so is using their kit.
This thread is dealing with the Diemaco (now Colt Canada BTW) which has been in British service for a while with UK SF; the above pictures seem different from the L119A1 SFW used by UK SF and from the C8 used by the PF.
Don't know about him, but I was out there at the same time and got chatting to a RAF Cpl ex-dog handler turned CP for a 3*, who let me handle his weapon (fnarr - sorry couldn't think of better way to phrase that). They are definately Diemarco's, modded for their CP role, fore grip that turns into a bi-pod (nifty) and a designator on the front.
I'm not a particulalry gun walt butI quite liked that, light, nice size and according to the guy accuarate.