It sounds the same except the instruction course is not absolutely necessary. I do medicals on CDL applicants since I am an MD. Some of the applicants are not "rocket scientists" and the place where I took the test has a course for them for up to 6 weeks! This includes "Class A" which means tractor-trailers and is both classroom and practical.
They told me I was absolutely the 1st person in Alaska to take the test with an "RV". Only this one place in Anchorage (largest city in the state) does the test.
Again, if you can read fast and retain it, and have a good memory, and most important know your truck inside and out, it isn't difficult.
Due to reciprocity treaties, I am now "good" all over the world, at least in countries that have signed the treaty. My licence does have a limitation of "automatic transmission" because the vehicle has an autoshifting manual. Which is fine because I got it exclusively for the use of the same vehicle. My licence is "Class B", which in NA means rigid trucks, any weight, including air brakes.

Charlie

Think your class B is same as our class C then, It allows you to drive any weight as long as its fixed. I think theres further test for hazardous cargoes over here too.
The testing isnt too strict in teh Uk because if you look at the rigs used by courrier companies and mail order stores/home delivery companies they are always covered in damage from hitting things. The test course up here was the same route I did my motorcycle CBT training, the truck drivers learned on the industrial estate before having to do a little bit of town driving, dual carriageway and a reverse test plus emergency stop.

I saw the rigs on jacksons they have mogs and bedford ex mod with troop carrier boxes which may make a good camper base although they have huge windows all round. They look the same kind of construction as the nefaz boxes used on kamaz and ural mining trucks. They also had some other boxes for sale, the mobile bakery one with slide out side was huge.
They also do big MAN 8x8 with a box on the back and they had MAN KAts as well chassis only. Theres a guy in the states thats has a camper built from an ex US army one in Alaska somewhere. ITs on olive-drab.com

I think the boxes are actually made by jacksons themselves as it says they can do the work. Withams Mod sales also have things like command boxes ect pop up in both their autions and tenders now and again.

I do wonder what jacksons are charging for their vehicles, Is there any reason no one wants to use the merc 4x4 1017 trucks, as I have seen a few german camper conversions on those.