Hi Tim,
As there's quite a few S2 owners on here I'm sure you'll get a more positive answer than my guessing, but here's a thought to be going on with. The production milestones quoted in the Robinson & Francis book don't refer directly to a change in steering column, but they do list dashboard changes. I'm guessing that if you went from a dash mount ignition to a column mount, then unless they used the hole for something else, you'd also change the dashboard ?
If that holds water, then you can see from the list below that the dash was changed for the 54, but not changed again on the introduction of the type 65 at chassis 1066. The dashboard change came further on in the run, at 1173 for RHD, 1387 for LHD.
I could just see Colin discussing it - "let's change the Europa and tidy up the dashboard" followed shortly by "but we've all these bits left over, hang on, let's use them up first....."
0645 Introduction of Type 54 Series 2 Europa
New bodyshell
New doors, interior trim panels, frames, quarter lights electric windows and door locks
New dashboard
Modified pedal assembly
Revised chassis
Optional Phillips radio
0920 New radiator thermal switch
1066 Introduction of Federal Type 65 Series 2 Europa
Revised bodyshell
New doors, internal & external locks/handles
Revised chassis
Modified wiring loom for brake failure & hazard warning lights
Modified demisters
1173 Revised dashboard, RHD cars
1330 New tunnel cover
1387 Revised dashboard, LHD cars