Problem with Servis M9503 - Stuck in middle of programme?

Put a load of washing on yesterday but the programme appeared to get stuck on the first part of the wash programme. It stayed on the first light on the washing progress panel which I think ids the pre-wash part. I thought last night I'd leave it to see if it 'un-stuck' itself - but it didn't - it went on for 5 HOURS (!!!) before I decided to switch the machine off.
I've put it on again today but the same things is happening. I've had a look and the water is going in but it's not moving onto the next part of the cycle (the rinse).
Does anyone have any ideas what I should do?