The best Ashdown cab I ever had was the BP1510, with 2 10"s and a 15" in a tall-ish enclosure. They haven't made it in quite some time now though.
I've been running mine into a Barefaced BT2 and I have no complaints. I did get to try Ashdown's Rootmaster 2x12" cab from a few years back, and it sounded good, but couldn't handle all that much power on its own. I'd quite like to try a pair of them and see what that sounds like.
I've just got hold of a RM800 Evo III, and, sadly, it's the first piece of Ashdown gear I've had a problem with - something's up with the input gain (not sure if it's the knob or something else), so that's going to have to go back. I've had the original and Evo II versions (the Evo II is my workhorse) and never had any issues, so it's a bit disappointing. Their stuff is usually absolutely bulletproof in my experience. Should have held out for the new UK-produced version, really.