This sounds like a hardware fault, most likely the motor, it will require an engineer to come out and strip it down and test the components.
If you would like me to recommend a repair centre, please provide your post code.
I have referred other customers in your area to DR Electricals, and always had positive feedback from customers who have used them.
They can be contacted on 0116(###) ###-####or 01509 272039
The Siemens and Bosch seem to be the ones I see most issues for, and the replacement parts are more expensive than others.
However by in large non of the appliances are made to last these days, I would really look at the price of the appliance against how sturdy the door is to get a feel for quality.