I've had my hawk wagon for a few months now done 6000 miles roughly. Yesterday in traffic on the motorway the engine light came on on me. The car was still running and idling well so I nursed it home and scanned it. It came up with p0021 timing advanced Camshaft Position A - Timing Over-Advanced or System Performance (Bank 2). I've done abit of searching online and checked the oil level which is good (changed just under 5k miles ago using Shell helix 5w40) the cambelt was done by main dealer at 130k miles in 2017 and its now on 138k and looks OK. I've read about the screens in the banjo bolts, would this be an easy enough job to do or would you recommend getting it booked in a garage? Last thing I want to do is mess something up.