Speakers s/h up to about £800 - recommendations please

Couple links for you on room treatments

Real Traps

Yeah, I know, it's a US based outfit, but their 'How To' pages and the various videos are pretty good as an introduction. Ethan, the guy who owns the place is a regular poster on the Martin Logan owners forum - seems like a very sensible, down to earth kinda fella. That said, the video showing his lounge set up is a bit scary.

Alternatively, if you want to go it alone, you could do worse than looking up

Bass trap self build

or

Cheap 'n' dirty Ikea bass traps

or

Acoustic Tweaks rather stylish home made traps

All much of a muchness, but most are adaptable in one way or another.

Hope that helps

Neil