Definitely good advice. It depresses me how many people, new to campers, are having miserable experiences due to bodgers. It happened with beetles in the 90s and its happening again, only they seem to be better at hiding it. I have seen some amazing sculptures in filler, some of it good enough to fool even an enthusiast. Crawling around underneath is definitely the best way to check, as they don't count on people doing it. And they're right! Before I sold my old van, I dealt with the only rust patch on the underside, a 2 inch square patch of rust in the driver's floor. I spent several evenings grinding it back, making a panel, butt welding it in, dressing the welds, etch priming it, seam sealing the joins underneath, topcoating it and then waxoiling underneath. I figured no-one would buy a 40 year old van without lifting the carpets. I completely wasted my time. Not a single person who looked at it lifted the cab mat or got underneath. Most thought the fact that the paint was 8 years old was a downside, rather than reassuring. On imports, the only point I would add is not to forget that none of them will have been cavity waxed, which means they rust from inside out. Even in the desert some moisture comes out of the air when it gets cold at night. So every night, every box section gets just a little moisture inside. It's nowhere near as bad as in a wet climate, but it catches people out. Unless it's accident damage, the first time you see rust, it has gone through the steel completely and the surrounding metal may be thin. A bubble or two won't mean sanding back or touching in, it will mean welding. Finally, it still amazes me how many people pay out to have bodywork restored and new paint, but then don't cavity wax every box section. There are a lot on a bus - A, B and C pillars, the sills, front arches and steps, the front top hats, the front deformation panel, the rear quarters, the chassis rails, the box sections round the engine lid, plus 5 doors. It takes several hours to do them properly and a lot of cavity wax, and that's without any underbody wax protection. It's also a horrible job, but without it I can't see these imports lasting in the UK.