The support bar that has the two bike stabilizers is down in this picture. You can see how the rack screws into the chassis.

The support bar is up in this shot. It is ready to add two bikes to the rack.
I have a bumper insert rear bike rack that worked on my 2015 Countryman. It may work on other years and models as well. It has threads that screw through holes in the plastic into the chassis. It is very elegant and holds two bikes. If your Mini has the removable plastic inserts on the rear bumper, it will probably work on your car. It won't work with my 2019. I'm asking $200. I am located in Colorado.