because the water could seep through the joints between the new tiles and sit between the two layers and affect the seal and also raise the height of the floor and affect the slope to the waste outlets..but, why do you want to retile if you're not using the bathroom??...for immediate resale consider bathroom wall to wall bathroom carpet, new wall paint, new vanity, taps and light fittings which should also be cheaper than tiling over the top and, if it's not allowed by the body corporate, it will be a risk to future sales as it should not satisfy a proper building inspection

Hi there, tiles on the floor of a bedroom? It sounds a bit cold underfoot unless you are having underfloor heating installed, but then perhaps you are renovating in warmer climes than where I live! I would recommend going for a matte or satin finish in the bedroom as the gloss could look a little sterile.also If you have a connecting ensuite, you wouldnt want to run the risk of slipping on the floor if you have wet feet :o

quite possibly, that was going to be my next solution! heading back there in a moment to check it out. the existing tiles have been layed quite nicely/flat so i dont think tiling over would be an issue

How about limestone ?