Thanks Mattysupra.
I don't think we can lay the wood flooring on top of the wooden panels because of the current skirting height and the radiators/piping.
We also need to replace some of the wood panels so ideally want to remove them and lay the floor on the polystyrene/water-proof membrane.
We've just bought a new house and the flooring downstairs is a floating floor.
I'm not sure what the subfloor is but it has polystyrene, a waterproof membrane and then plywood/chipboard 'loft'-type panels on top.
Does anyone know whether I can take some or all of this up to put down wood...