Bradshaw 500 oil cooled twin engine strip

We are stripping the Bradshaw 500cc oil cooled twin in the Brooklands Zenith due to persistent over oiling issues in the heads. Included are a few pictures for those interested in what is inside the crankcase.

pic 1: machine in question

pic 2: engine out of frame

pic3: crankcase split (cylinders removed and not shown)

Checked over the bore and rings with micrometers, very little wear/ovality (2 Thou). Bores measure up to be +20thou. Some minor scuffing on bottom edge of both bores. Hence whilst we will deglaze bores, this is not the source of the over oiling to the heads.

Checked over the oil pump, simple gear pump, seems to be fine; however no apparent means of pressure regulation.

Hence investigation has focused on oil coming out the wrong places! The most likely is the offside plain crank bush through which the oil is fed under pressure to the crank, routed to big ends and then thrown out around the engine, to cool and lubricate. Neither the bush or crank seem worn, just a reasonable working clearance.

Does anybody know if the crank should be fed by a quill (as none is present) , also if the bush should have some form of oil seal (as the bush has an empty counter bored slot half way along it length). If these are needed it may explain the over oiling into the bores?

advice/information appreciated
Ian