I just purchased a 2005 cooper with 16 inch runflats and have been tearing my hair out initially trying to find a suitable space saver
Then My son visited with his Suzuki Swift with 17 inch alloys with very low profiled tyres and it suddenly dawned on me to check his spare.
You little ripper,his spare is a space saver of 15 X 125 X 70d
This fits perfectly over hub and studs and easily in the boot or if so desired under the floor once a mounting kit or similar is made.
I removed the plastic cover from underneath and if I was to cut the well out where tools are kept could probably mount a stock standard 16 inch allow and shove jack and wheel brace inside cover on right wheel arch and have a flat floor welded in place of tool compartment.
I have only had this car for a week having sold my old MG TC.
Wouldn't you think Mr BMW would of sold more minis here in Oz if only this option was available as no wants runflats.
From experience most tubeless tyres only leak slow and if noticed can usually pump up and get to a tyre place where they can get them selves dirty.
Hope this helps