I simply typed in "marble restoration " and the search engines did the rest..............found another yesterday who are London based and look very good...............Posh floors !
Ian, not so sure about " hard floors " being the best bet for Flood Prone areas unless they are Tile on Concrete.
I would have thought the best bet would be " no living space below possible flood levels " this can be determined from previous records, adding a couple of feet, for safety.
If I were an insurance Risk Assessor, that would appeal to me.