Hi lads, thanks for all the input, its really good to of found this place and i realise that everyone is going to have theirown opinion on things....
I think i'm gonna go with screwing 9mm ply over the top of the chipboard, posibly 12 if the height allows, and obviously a good flexy addy, i normally use the topps home brand and not had any problems with it so far... although this one will be haveing BAL .Oh and there is NO heating system in the floor
paul, its the customers decision not to take up the chipboard, its a very large house and its spread over 4 different rooms, would make a much bigger job and i think i agree with the customer that it's probably not nesesary, as long as i can get the rite thickness of ply in place.
kev