starting handle oil leak

[James Baxter]

We have an oil leak from the starting handle.
It leaks out of the front bush in the front cover while the engine is stationary.
Inside the timing gear cavity in the front of the engine, there is a square cast oil return kind of chimney, back to the main sump
This controls the oil level, all of which is dumped by the oil pressure relief valve into the timing gear chest.
But the level is controlled to a level, which is about 1 inch higher than the starting handle shaft.
So we always get about an eggcup full amount of oil spilled after every run.
Before we fit an oil seal in the front of the timing cover....... are we missing something?

Has anyone fitted a full-flow oil filter , screw on canister type on an early vintage engine?