Thanks yet again for the informed reply Sunny.
Ive been really slack in doing my van, but am leaving the Defence force and taking a trip to Tassy, so want to set the van up a bit better.
I went to Bunnings on Saturday to get a single sheet of 9mm Marine ply to do the floor. Biggest available is 2400 x 1200 so Ill need 2 to floor the LWB van.
Do you recommend cutting the second sheet length wise or 2 sheets joind mid van?
Ill then use checked lino to cover the floor.
Yep, van is fully Dynamat Extremed and then sound deadened with suitable batts.
Thanks again mate.

Ken