Well i took the wheels off.........
The good news is the wheels are Genuine Rover. Each one had a Rover stamp on the inside (see picture). They are all in pretty poor condition and two tyres are bald, so replacing the set seems like the way to go.
As for the spacers. All 4 had spacers that were about an inch wide, with extensions! The rear drums are the later type with the built in spacer. These spacers were huge, not the 5mm - 10mm people mentioned i might expect.
With the spacers removed the wheels all fit and there is still enough clearance at the rear (Will need to test on the road). As i cant drive the car, I've not really been able to test the front lock and i was a little tight on space in the garage. The arches do now sit well over the wheels. Without parking next to another Mini, i honestly cant say if its right.
I dont think the spacers were put on for any other reason except to widen the stance. It did look better being wider, but i would rather put wider wheels on then those stupid spacers.
The car still has negative camber at the front and appears to be sitting low. Couldn't even get a trolly jack under. I have two new shocks on order, not sure if the camber is related to a negative cam lower arm mod, or the cone and knuckles that have been mentioned.
Oh and to add to the stupidity, one drum and one calliper were painted blue, one calliper was red, and the other drum was unpainted. None of them were even painted in high temp paint, so as you can imagine they look a bit of a mess!