Miele W844. Slight burning smell. Is it the belt? ?

I have a Miele W844, 8 years old. I had a strange smell, like a dentist's drill drilling, a friction type smell,coming from my washing machine 3 days ago. It had one item in it at the time, a blanket. I stopped the programme and then drained and spun it. I attempted to start the wash programme again and this time it switched itself off after 5 minutes, accompanied by the same smell.
We took the top off the machine to take a look and the smell seems to be coming from the back of the drum. No sign of burning or scorching though. Had a third attempt to do a machine load and it turned itself off again. I've been away for the weekend and have tried it again today and it's done 4 full loads without a hitch! A tiny whiff of the same smell on the 2nd load and then nothing else.
Miele charge £97 just to come along to take a look.
Is this a simple fault or repair, like a new belt that drives the drum(I'm not technical !) Can I afford to carry on using it like this or is it dangerous do you think?
I'd be grateful for any feedback anyone may have.
Thanks .