On Sun, 2 Aug 2020 10:37:25 +0100, Roger Hayter wrote:

Thanks, that's helpful. But doesn't help with the elusive marine
plywood which is allowed to be wet! Perhaps it never existed.

Well some form of ply wood existed that didn't fall apart when it got
wet. There was a bit here, untreated/paintted, used as a sign propped
up against a wall so lower edge on the ground that was still sound
after a couple of years. Bit moss and algae covered mind...

--
Cheers
Dave.