Arthur wrote:

I tiled my kitchen floor last year and made a pigs ear of it.
I think I should remove thse tiles and start again.
I suppose a SDS chisel is the only tool for this job
as beneath the tile cement an area of the concrete floor has
floor levelling compound on it.
The kitchen is about 3m x 1.8m. How easy would an sds shisel
remove this stuff. And will I need to be as fit a race horse to do it?

Depends if you buy a £30 heavy or £100 light tool. Given the area you've got
to cover I'd suggest at least a green Bosch.

I could leave the tiles and use more floor levelling compound then
tile on top which would raise the floor level about 15mm.

If you're happy with that then do it.