So - more extreme project creep!
The early cam housing covers are renowned for there capacity to leak so, as usual, I've gone for an extreme solution
This is a casting I've had made which I hope will permanently cure the problem:
After machining I've bonded it to the original cam housing:
Clearly I've copied the SE's approach to providing a flat surface to seal against. Time will tell how good the one-pack heat-cure epoxy is!
The eagle-eyed will also have noticed my new oil pump design:
The oil pressure relief valve (prv) doesn't work as well as I'd like - oil bypasses it even at 20psi, so I'm running an external, adjustable prv with bypassed oil returning to the sump - not the inlet of the oil pump.
Feel like I'm making a bit of progress at last
Pete