Just had a call from the dealers as my car is in for a service and MOT. They've mentioned there was a small bit of oil coming from the rocker cover, nothing to worry about but they had to mention it. They said it's likely to be the gasket needs replacing but I should check it in a few months. Have any of you changed the gasket? If so, is it easy? Any special tools? Any tips? What was the part number and how much was it? Car is a BLB 2.0 TDI.