J2210 is not on the current Register, I'm afraid. Perhaps Robin can tell if it's one of those that were taken off the listing due to lack of contact over the past umpteen years and it has in fact been heard of post war after all?
A bit odd is that the Service Files show one J.H. Heyman from London as the first owner, there's no mention of Kenneth Rankin ...
Julian Evers quotes MG 1932 as J2210 for the "chassis files", with the dates as quoted in the piece. I would have thought a fairly prestigious registration number for the date. Did Rankin have any connection with University Motors?