damp is your biggest worry with any older 'van. fortunately the awards of that era were pretty solid.
the main areas to check are the four corners, but particularly the rear corners as this seems to be where these 'vans fail.
check the rear floor as well as they can rot at the corners, sometimes the corner steadies will give this away if its bad enough.
if its a boat roof type, which i think it is, check carefully along the middle for signs of leakage, although this isnt normally a problem with the award.
other than that make sure everything works, make sure the hot water tank doesnt leak, its an expensive fix and you dont want to be home when you find out.
quickly check the electrics including the road lights. you wouldnt be the first to buy a 'van and then spend days trying to get all the lights to work.
check the inner sidewalls of the tyres, theyre usually forgotten during cleaning and tarting up and you'll know right away if they're healthy. and if an owner doesnt use good tyres what else dont they do?
and lastly, trust your 1st instinct. if you're not happy dont commit.