Quick update,
I got a mail back from Banks this morning, it seems that WOSP (the manufacturer of the starter motor
http://www.wosperformance.co.uk) made an error and put the wrong adapter plate on. So, false alarm, the correct size is 4.5" centers.
Many thanks to Andy for sending the photos of his bell housing, this was the "proof" that my bell housing was not an anomaly and got the solution found. Banks were great in helping to get to the bottom of it and I should have the correct plate this week.
The company I found to re-work the tach was
http://dandmrestoration.com I talked to them and they make in house a circuit board to modify the tach to work with the MSD. Seemed very knowledgeable to me.
Again thanks to everyone who posted, I did not want to be a "the sky is falling" poster, but when Richard at Banks told me that it should be 5" centers and I don't know even 1% as much as he does about Europa's I had to believe him.