Problem Fixed! A big thanks to all those who have posted with advice.
The part ordered on e-bay, to which a link was provided in an earlier post, was the wrong part.
The CPS on my car only has one lug to secure the electrical connection, the one sent had two locating lugs.
Sourced another CPS locally and all is well now. Engine ran for an hour on the driveway and then did a 10 mile test run.
The correct Bosch part number for my car was 0 261210 171
An E8 Torx socket with 1/4" drive and universal joint was very useful in doing this fiddly job.