A man in his shed can easily repair these things in a couple of hours, that's provided the problem is the usual one that crops up 95% of the time (whereby the brushes are sticking).
What I'd really want to know, is how does he cure the problem? Does he simply open the motor up, spray some electrical contact cleaner over it, and put it all back together (in which case it'll work again for an undefined amount of time, but WILL fail in future), or does he do something to actually prevent a recurrence of the problem?
Funny thing is, if any of our members have this problem, and they're near me, I'll happily have a go at it for the price of a pint plus whatever spare parts are needed!
Steve