If someone with a space-saver can clarify the following: some space-savers can only fit the rear wheels (sizing issues). A front puncture means swap good rear to bad front and put space-saver on rear. Also some space-savers have a distance limit as well as the 50mph limit. Does the mini space-saver have one?
Manafacturers are pretty appalling about making this info clear - especially considering it might be dark and wet (and you'll be stressed) when you need to know.