NoSpam wrote:

I'm back to my original quest - where can I get some 8 or 10mm thick
toughened glass shelves (about 550x350) at a sensible price?

I've had toughened glass (not that thick though, to be fair) from a
local upvc window supplier/fabricator. I can't recall what it cost me,
but it certainly wasn't prohibitive compared with the equivalent in
standard glass. Maybe you just need to keep looking?

David