This is an interesting quandry because according to the Haynes manual axle stands should only be placed under the jacking points. Jacks including trolley jacks should only be used under the vehicle jacking points. Never put the trolley jack under the "sill,engine sump, floor pan, subframe or directly under any of the steering or suspension components". This from the people who claim to do the work in the manual themselves. So for a gold star who knows how to get an axle stand under a jacking point that has been raised by a trolley jack .
When I had mine up on stands for a couple of days, I jacked on the jacking points (eventually...broke my dads 15 year old trolley jack in the process), then placed the stands under the frame, front and back.
My Haynes says "axle stands positioned under the vehicle jacking points"
I usually put my axle stands where the suspension arms locate on the body but am careful not to put any weight on the suspension arms themselves. It's annoying there isn't an obvious official placement but I suppose Mini want you to take it to a dealer .