I worked out of the back of a car for more years than I care to remember, first with ladders and then with WFP, and it matters not a whit whether you have a van or a car, you can still be driving around without insurance in either vehicle.
And even if you don't have insurance, that certainly doesn't make you a cowboy, it's worth bearing in mind that public liability ISN'T a legal requirement, unlike employers liability which is.
Whoever is the guy who will clean the window up on the roof may well only be some young chap who isn't fully aware of H & S, or even one who thinks it a fuss about nothing.
Just 3 years ago I'd have thought nothing of doing a job like that, I wouldn't dream of it now of course.
There is another window cleaner in the Chepstow area that doesn't have a computer, thinks WFP is crap and happily works at the top of his (at one point) very rickety ladder.
I can't stand the guy, have no time for him whatsoever, but he isn't a cowboy and he has been going as long as I have.
Providing this chap had a ladder long enough, I've no doubt he would do this job like a shot.....
Mind you, as I can't stand the S.O.A.B I'd probably try at get him reported
Being on this forum has made us all very savvy with regards H & S, but many out there don't have access to a computer or this forum.
Having said that, the company employing him to do the job plainly isn't fully aware of H & S, from their perspective, having someone working off a ladder on their site is foolish, if things went wrong, they would be in the dock too.
Ian