OK...damn glad that I got rid of the second tiling muppet. He'd used massively thick beds of tile adhesive (costing me a fortune in the process) rather than build up with other stuff like cementitious boards or self-levelling compound. As a result, the muppet left a load of voids underneath some of the tiles.
How did I discover this? The sound of a crack as I happened to step on the wrong place was a bit of a giveaway. So remove the cracked tile and can see lots of voids under other tiles.
So I plan to pour in some runny self-levelling compound as I don't really want to take them up.
The bad news was that I clipped one of the adjacent tiles and so that one had to come up as well leaving a bed of tile adhesive.
So question, chaps ....
Could I get away with putting down something like a thin coat of No Nails or gripfill or something similar rather than go through the fag of getting up all that tile adhesive ?