Morris Minor Owners Club

Watching Dave the other day there was a re-run of Top gear and the ice driving race with the Morris Marina. I noticed something the first time I saw the prog and again on the re-run and it's still bugging me as to what the answer is.
For the race, the supposed 'standard' Marina gets shod with 5 stud wheels.

From the way the wheels were spaced outwards, I suspect that there were adapters of some sort used.