Well I now believe that I’ve found the oil leak. There appeared to be oil leaking from the petrol pump gasket. I removed the heat shield and redid the gasket. Drove to TOC meeting Sunday and there was oil everywhere including inside the wings. Got back and my brother in law spotted a threaded hole next to the petrol pump. This hole was threaded M7 and is not shown in the parts manual for th ID19. There has never been a bolt in the hole for the 12 years I’ve had the engine. Found and inserted bolt which should cure the problem.