My previous cars, and now my Mini spend 3 - 4 months stored. Looking in the Bentley manual I find zip. Looking in the owners handbook it says to 'ask your Mini dealer.'
So, any suggestions?
What I will do is up on blocks in a garage with the possibility (may not have an outlet in the garage) of a battery tender. Can the car survive without the battery connected?
I'll clean and wax it with a cover over it even though in the garage. I'll fresh change the oil and filter, Stabil in the gas with a full tank, plug the exhaust and intake to keep critters out.

 

Figure out a way to plug your intake for the A/C ventilation system too. I have read threads on here about mice making nest in the cabin filter area.

 

You may also want to put something around the perimeter of the car to keep the critters from chewing on wiring or setting up housekeeping in the engine bay or elsewhere. I agree with you about trying to keep the battery attached on a tender if possible.

 

+1

 

I had a problem with mice getting into one of my cars. I they didn't get into the wiring, but the smell took a few weeks to fade. That car was parked under a tree near in contact of some shrubs and tall grass. The next year I parked it in a wide open area on the idea that the critters would have to run across the open space, risking attack by something. There were no problems that time.