Thanks for your response, Ian; I guessed you would be 'the man'.
I've not stripped the shutter yet but if I remember, the spring roller is brass. So- I remove the outer wood sleeve and the blind and then clean - WD-40 etc. and wash the whole thing. After that, is the whole roller soaked in the meths and IPA and allowed to dry or somehow dripped in to the inside?
I also have a small shutter for front mounting. It has only a metal ring for pushing on the lens which seems a bit fraught. Should it have a rubber or velvet type lining?
Thanks again. Colin