OK, after further investigation I can see that the two items in the picture above are the felt washer and outer space.
In order to access the actual oil seal I have to take off the end cap which is held on by 3 screw in bolts (In the picture they look like rivets as the screw heads are full of dirt and somewhat burred over.
Before I go to the trouble of attempting to remove the end cap (and potentially failing and/or ruin it) is there any mileage in trying a solution which when added to the tiller oil is supposed to stop oil seal leaks. Has any one ever tried this with any success, or is it not recommended?
I am looking at this option because no one seems to know the size of the oil seal, which I suppose means I might not be able to source one. (Has anyone here ever changed the tiller shaft oil seal on a clifford mk1?)