On 1 June 2016 I put my 2012 into storage, and unfortunately its one without power so couldn't use my battery tender.
On 24 Feb 2017 I'll be taking it out of storage, about 9 months in storage.

I disconnected the battery, and will stop and pick up one of the portable Lithium jump starter batteries.
Looking at the typical self discharge rate, there's a remote chance there'll be just enough in the battery to start it.

These key Fobs have rechargeable batteries which will most likely be nearly discharged, but hoping this wont cause a problem, guessing that the Fob has RFID to allow the car to start - am I right in this regard?

 

I do not believe the keys are actually recharging. I know the batteries inside of the fobs are like watch CR2032 batteries.

I doubt it will have the power to start it after such a long sit, so I would have the jump starter handy just incase..

Why so long without your MINI?!

 

Yup..

 

Some of them do have rechargeable batteries.
On my way to collect the Mini, I plan on stopping at Autozone to buy one of jump starters.
I've read online that the self discharge rate of Sealed Lead Acid (SLA) batteries is 3% per month, so a small chance it would be up to the task.

I am abroad on business.

Thanks.