Hi denis,
I don't now how I missed the fact that there was another fellow countryman around but somehow I did...
Only a couple more and we beat the Brits and Aussies
I had the same issue with the plunger. The outer cover doesn't fit the inner very well also, which makes me think it has been replaced at some stage.
Like Bill, I got the invaluable dremel out and ground a little bit away on the inside of the cover until it cleared.
If its the outer cover, smear a bit of grease on the edge of the bigger pulley. Then put the cover on. The trace of grease the pulley leaves on the edge tells you how far you have to go
The SA didn't have this problem though, and also the outer cover on the SA fits the inner noticeably better