The SMMT created a Habitation check for Motorhomes many years ago, Its’ guide lines suggests the dealer should not only check the gas and electric ( 240 and 12 volt)instalations but also the bed make up, the windows, curtains and blinds, cupboard doors and many other things that the customers are more than capable of doing themselves.
We only do the things that you can’t do like checking the gas system for leaks, correct flame structure and Flame failure devices.
The mains for correct polarity and earth leakage. The 12volt system for charging and battery condition. Why pay for work that you could do yourself?