It’s also vitally important that the waste water system
It’s also vitally important that the waste water system is clean and works properly, this should have been done by the seller prior to them putting the motorhome up for sale so get them to show you how the cassette is removed from the toilet unit so you can see whether this has been done - it’s not a job you would want to do after buying! Make sure you shop around for the best deal, look online at plenty of models but don’t make any decisions until you see the motorhome first hand, no matter how many pictures you look at you won’t get a true feel for the interior spaces until you look around in person.