I don't mind doing it myself but the big barrier I find is access. The real advantage a pro place has is a ramp which makes the job 10 times easier.
There is a guy who advertises Waxoyl proofing frequently in MMM . I think he is in the Midlands. He always starts his full page ads with "I don't own a motorhome because I can't afford one, but if I could, I get it treated at (insert his name here)...."
To me, this puts you off at line one because it begs the question, if your service was any good you'd be making a mint and be able to afford several motorhomes... is it just me who noticed this?
I'd be interested to hear from anyone who has used his service. When I see the advert again, I'll check out the name and edit this post for you.