My three year old Volvo D1-20 has developed a small oil leak As far as I can tell the leak is in the gasket behind the timing gear casing. The genuine has done about 210 hours and the oil and associated filter has been replaced twice in that time.
It would appear that to fix the leak a new gasket is required but that involves removing the timing gear case which is not a trivial exercise.

Has anyone else had a similar problem and if so how have you solved it.

Have you nipped the bolts up on the timing case?? Be careful not to over tighten!!

Yes. No change

Wipe it down occasionally with an oily rag and go sailing.

Good idea