Ok, thank you. The car is currently undergoing quite major repairs and won't be back on the road for a good few months. I'm keen that new problems don't appear whilst I'm trying to reduce my 'jobs-to-do' list, but it isn't vital to get this sorted immediately.
I'll monitor the problem and go deeper (if reqd.) once the car gets close to being roadworthy again.
All your help is much appreciated, thanks again everyone
