Just thought I would post that my S is in for the latest cold start rattle fix.
It has displayed the absolutely hellish (worse than a 70s diesel) noise a couple of times only following the following procedure:
Park the car so that it is cold. Start up and reverse about 15 feet then forward the same (read this as me moving parking space as I was not happy where it was parked). Come back a wee while later and it makes "the" noise.
I managed to video the noise on my phone to show dealer. They are doing the latest fix tomorrow.
Thanks to Peter Vardy MINI for being so understanding and not saying that they have never heard of the fault or refusing to fix it until they heard it.