Got the car back yesterday.
The timing belt had slipped knocking the timing out. Cost us £65 in labour as it wasn't covered on the warranty. Lookers Ford were totally useless in the end, so I'm going to be writing a letter of complaint over the weekend about the service we received, and the useless warranty they have sold us.
I now need to get the belt replaced and a new rocker cover gasket, so I'll be arranging for a full service to be done on the car sooner, rather than later.