If you go the redundancy route and you have other employees who have worked for you for less time,. he would have a case for unfair selection. This is the equivalent of unfair dismissal.
If you make him redundant, you're not supposed to fill his job for 6 months (I think) because you are making a position redundant in the first instance - a position that happens to be occupied by him. A lot of regs are waived for companies with less than 5 employees - not sure which ones though.
I say that if he continues to work for you, you have to let him continue using a non ladder method at least for the top floors. You could end up in deep doodoo otherwise.
Another thing that comes to mind too: I found that when I've subcontracted domestic work from other shiners, the rate of complaints is always higher than with my own work (I rarely get one these days). I don't treat the subbie work differently from my own. I think it's just easier for customers to feel that they can complain if they have a buffer zone (you) between themselves and the cleaner. It's easier to complain
about someone than
to someone.
So as far as work quality goes I think you ought to check on his working methods before acting. As for the van - well - it can happen to anyone (I reversed mine into a mini skip a while ago but that's my privilege because it's my van).
. Annoying I know but no-one's perfect. You may have some justification for charging him for a repair - or at least the excess if an insurance job.