It all depends which axle you have at the moment. The early S11 has the Nuffield- type axle, the alter ones had the A-series axle. They changed over around '53-54.
If your axle has a 2-piece casing, then that'll be the Nuffield one, if the diff looks like it'll come out in one piece through the front of the axle, then it's the A-series one.
Later diffs will bolt into the A-series axle, the earlier axle will need to be chancged for a later Minor on, it's a bolt-in swap.
I'm pretty sure that the Nuffield axle had a 100mm PCD (wheel bolt pattern), whereas the later cars are 4" (yes I know it's close, but not close enough!).
You'll need the later front drums, hubs and wheels if you want to avoid carrying 2 spare wheels.
Actually, due to Morris assembling guns for a French manufacturer(!), there are metric threads on the MM series. The head bolts on the side-valve engine are Metric fine threads, and other metric threads can also be found on the sidevalve engine.