That's not a caravan Jay, this is a caravan.
Check for damp behind the seats/bed and open all the cupboards, look for signs of fresh paint and silicone. Be cautious of nice smelly air-freshers, these are often used to disguise the smell of damp.
Also check the floor for delamination, this is when the two laminated 6mm ply surfaces separate from the foam insulation. Its an easy fix, just some one shot poly adhesive to be injected into the floor and plugged with some wooden dowels. Job done.