So...two weeks on in the lounge floor saga...it's almost sorted.
Surveyor is being an enormous see you next Tuesday and won't admit any liability or not doing his job. (considering threatening him with a letter to RICS...although that process takes 3 months minimum apparently and we couldn't live with no lounge floor until then so the evidence is gone...)
Solicitor has said there's no point at all in trying to get any money at all out of the previous owners.
Lots of unexpected money pissed down the drain but at least i can jump around in the lounge again now. Found some nice engineered oak to lay too, with a little help from a friend. Things are looking up - even if I'm a bit (a lot) lighter in the pockets.