To insure as a campervan the vehicle needs to satisfy the items on the list on this page:
If you dont have double bed, water tanks, etc, you are unlikely to get insurance as a campervan.
I have a Leyland 1991 van which I use as a basic camper - previous owner had put storage seats in the rear which convert into a bed but there is nothing else in there. Does anyone know if I can insure it as a camper even though on the log book [V5] it says 'Leyland van/side windows'? To insure it as a van is expensive and as I only use it occasionally and for the sole purpose of camping, it seems unfair.