I think there are proprietry fillers you can buy (find a good plumber and pick their brains!)(ring up a good plumbers merchant)(look on the net) but youd need to uninstall and reinstall the shower tray or pay a man a lottery win to do it for you. If it were me I'd have a go at tiling over with mosaic ceramic tiles and waterproof tile cement and grout (bearing in mind the weight factor)...if you are at all diy minded...dismantle the shower..chuck the tray and cement and tile the base
sally anne
November 2009