In the time you've spent posting on here the ply could have been out 
Good point - well made
I emptied the back of the van, having decided to take the floor ply up.
30 minutes later I haven't managed to get any of the screws out (and there are quite a few)
I'm either useless (most likely) or the chippy who owned the van before me put the ply in well to stop divs like me from taking it out
