Wasn't this one up for sale last year in Nuneaton...? Got a friend to go look at it and report back then for me. General report then was scruffy, but usable.
I notice in the description it has a fuel tank bag so that it can run on unleaded. May have valve seat recession then!
Provided it has not been relying on the 'bag' for too long it may be ok, but fuel additive or hardened valve seats are the only reliable solution. PC did a test on one of those bags on a BMC B series engine a few years back and knackered it!
Just been to look at this camper its full of filler , all the flutes have been filled as has the roof in fact there are no gutters as they have been filled flush with the roof its a shame as was intrested in buying it