Dyson CR01 f11.

I post this here for information only. If anyone has other experience of this fault though, it would be interesting to hear it.
Went to look at a Dyson CR01 yesterday with fault F11.
I did a search on here first and went prepared with 4 sets (2R,2L) of Ceset brushes as I learned it was no m.a. and there are twin Ceset motors.
Tried the reset a few times, no joy. All the brushes were plenty long despite five(?) years of heavy use. (Although Dyson may have been there and changed them under previous management.)
Anyway, the customer was a bit of a whiz at internet searching and had already turned up this thread on “howtomendit”.
http://www.howtomendit.com/answers.php?id=3817 (Best read from bottom and move up the page.)
(It took me about twenty minutes to find it just now despite knowing the site it was on – there are multitudinous CR01 threads on there, mostly useless.)
It didn’t help me as the module fuse wasn’t blown and as the customer was a backpacker hostel anticipating a busy bank holiday I advised him to get on to the manufacturer. He got them on the phone right away, they said they’d have someone there next day and would do the job, whatever it took for £99 all in! And this is Penzance!
Anyway, hope this might help someone sooner or later.
Mike.