An oil leak originating between the big end and gearbox got the better of me, so, I removed gearbox and flywheel cleaned it all down and the culprit revealed itself as a weeping big end cap gasket..... I was dreading the oil seal.
Anyway, on removing the sump I discovered this pile of fibrous crap surrounding the pick up strainer and in the sump.
If no filters were ever used my two assumptions are a home made filter inserted inside the strainer that has broken down and by some miracle made it's way through the oil system without blocking any oil galleries etc or someone absent minded person (for a better word) has left it in the sump?
Happy I decided to replaced the sump gasket.
Cheers