We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Paul Giverin
saying something like:

I'm in the process of doing my bathroom and I've just laid the floor
with 10mm thick tiles. Because of the wooden floor, I used some BAL
fastflex adhesive and I'm thinking about using this to fix the pan to
the floor. I've done a test piece using a couple of bits of floor tile.
The adhesive seems to be really strong and I'd like to use it without
screws but I'd like some reassurance. Is it accepted practice to use fix
a toilet pan to a tiled floor in this way?

You could use PU foam in the same way - let it set and cut off the
excess. Pretty solid fixing, ime.
--

Dave