It was an engine management warning light which when plugged into the diagnostic system gave an coolant system error. The engine temp was running hot and the fans were working a lot harder than normal.
I've had part of the pump switch replaced, but that didn't resolve the issue, so it's going back in for a full pump replacement (total cost around £800). Not exactly ecstatic about having to get out replace on such a low mileage audi, so will definitely try contacting audi direct as the dealership wasn't entertaining taking any of the hit for it.
Have folk had success taking this route before?