As an aside, a lot of ply came from Russia before they decided to annex Ukraine. Once that supply line dried up there was a lot of scrabbling around to find alternative supply. Consequently the quality of stuff that is out there is very mixed.
Once joiners had wised up to the situation some suppliers were left with stock they were finding difficult to shift.
Not sure if this situation has been worked through the system but take care.
I have used Richard Potter in the past. https://www.fortimber.co.uk/index.htm See Sheet mayerials page 3 for faced ply prices.
They used to sell Phenolic ply (waterproof deck board) in several thicknesses but currently only stock 18mm. That suggests to me that there are still supply issues.