The SAS/SBS/SFSG use it now actually :D . They categorically do not use the L85, which is very different to the regular British Armed Forces...it's all to do with attaching stuff, I believe (even though the A2 has RIS). And even anyway, Merlin's got a fucking SCAR...which I sorta justified by saying that the SBS have adopted it off their SEAL breathren, and in the time frame of four years, is still a vague-ish possibility. Same for Nikolaj- the F2000 isn't used by the Danes, but he uses it due to it's bullpup nature. 

Also, nicely posted. I am going to add something later on, but I think it's a couple still to post. Gonna be good :)