If you are seriously considering Mobile Servicing as a serious job change, then expect to have to spend out at least £10,000 to set up the business, with training, tools, courses, vehicle, spares etc, plus considerable ongoing costings to get fully qualified.
The MCEA course is a VERY BASIC starter course, and is just the very fine tip of the amount of work you will have to do to become fully competent BEFORE you can touch a caravan.
Even then, you will only be able to work on vans which are out of warranty as to maintain warranty you MUST be a NCC Approved Workshop,which is not easy to get and costs a LOT of money to do it.
With regard to having to be NICEIC and Gas Safe,that is not accurate, but you will get all the correct information from the MCEA.
With regard the collection and delivery of other peoples vans,,,,,,,,forget it,,,,it is a minefield of problems which, believe me, you do not want to get involved with.