Ask nicely at a mini dealer with your Vin number, and they might have something on record in the system. I did this when I was about to purchase my jcw, popped into local BMW, they plugged my key into their reader and printed off all its history for me.
I thinks mine too old to plug the key in spoke to them today. Gave me a list of dealers where it had been in. Told me to buy a service book and send it to each dealer and get it stamped
