bathroom tiling

You could just rip out the plasterboard with the tiles and then replace with new on the existing studwork. Probably quicker than chipping off all the tiles individually.

You will be incredibly lucky if you get the tiles off the plasterboard without completely trashing the wall.

You can tile over tiles very effectively.

When tiling on PB it is better to tile directly on rather than skim with pl aster first. I have found on plastered walls removing tiles often brings of f the top finish, rather than trying to restore the plaster finish I have u sed dry wall filler to repair large damaged areas. It is possible to apply it so it gives a smooth finish but even if you cannot it sands down very ea sily.

Richard

To offer a different option, in my opinion shower cubicles and perhaps even the walls above baths with showers are best paneled with Mermaid board or one of the other numerous similar products.

This random link mentions a few

Most of these boards are good quality plywood, normally about 10 mm, faced with decorative melamine on one side (and non-decorative on the other). They are not cheap, but they are relatively quick to fix, easy to clean, and avoid the problem of dirty and/or cracked grout. You could fit them over knackered plasterboard, or straight on the studding after ripping the plasterboard away. Also quite convenient if you need to make an access panel.