An update regarding this -
My son's MK5 Golf was in for service today at the local indy. I know him since he was working as an apprentice at another garage back in 2001!
Anyway, as I bought the car for him last year and was supposedly serviced by the independent dealer, I thought we'd give it a year and get a full service done.
Had the oil changed to Quantum Longlife, air filter, oil filter and fuel filter. Brake discs and pads around back were corroding so had them replaced too - all OEM.
He checked the spark plugs and changed them to OEM as well as someone had put in some fakes which had almost self combusted!