iajon wrote:

I've been looking for a while for a square 800 x 800 x 200 shower tray
without any success! Anyone know of anywhere that would be able to
supply one?

Get a quote from a sheet metal supplier in your area to build you a
tray out of stainless steel.
Search here for the saga of my stainless steel shower tray (still going
strong a few years after installation).
And "no" - it isn't cold underfoot (the steel is 1mm thick).

Mungo