* Removing existing tiles. Wall is breezeblock/plaster (1970s
construction). FAQs advise using a bolster chisel.

Use an SDS drill with a cold chisel attachment. I've never had much success
with a hammer and chisel. It tends to disintegrate the tiles into shards and
leave chunks on the wall. The SDS chisel, on the other hand, causes the
tiles to leap off the wall whole with excitement and stack themselves
neatly, ready for disposal.

And does the surface underneath (presumably chunks of tile
adhesive) take a lot of levelling off before retiling?

After removing large chunks, I go over with a belt sander.

Christian.