OK, that makes me feel better.

Eventually got the retaining collar off - had to turn the key way over to position 1.75 it seemed, but once it released it turned easily. Got the new cylinder in, put it all back together, car starts with original key.

One of the plastic rings around the ignition was brittle and broke somewhat during removal, but enough is still there that the DAS antenna and outer trim ring still sit securely enough.

Thanks to all who read and commented - sometimes the encouragement really helps boost confidence!

__________________
Charlie

---------------------------
'66 VW 1300 96K miles
'97 E300D 239K miles
'85 300D 203K miles (sold Sep 2012)