Anyone had deflation problems with these if left inflated overnight ?mine goes down to at least 4 psi or less from 14 psi .i think it could be the valve because I've checked for leaks on all the seams to no avail .i ve filled valve with water also and there are no bubbles .i just wonder whether the material itself is up to scratch too ?

Yep, you have a leak somewhere. I have a couple of inflatables in the family quiver & sometimes store them inflated, they'll lose a few couple of psi over a cold night or if they're left resting for a couple of days but they certainly don't lose 10psi overnight.

Try removing, checking and reseating the valve (you should have received a tool for this in the repair kit that came with your board) there's a rubber gasket thingy in there that can leak if not seated properly.

Cheers for that , I'll try re-seating the valve

Well job done. Took valve out cleaned and put back in .left it blown up overnight and it's ready to ride.

Good result, that's what we're here for