Came home tonight from 2 hr highway trip, 2003 R53 MINI was idling little rough when backed into garage, then when I shut off the ignition, the cooling fan came on suddenly sounding like I left the shop vac on....only problem was that it stayed on, and wouldn't shut off until I put the key back into the ignition, turned it to position 2 and then off again......Is this a bad sign ?

 

when my mom was driving the car it did this, turns out the oil was leaking out and the mini dealer didnt see this so they had it towed in order to repair it. Check your coolant and your oil level. This could be reasonable in your case because it was a two hour drive but better safe than sorry.

 

Once coolant reaches a certain temperature the fan will click on. It will remain on after the car is shut off if the temperature doesn't drop below that threshold.

It's normal...

If the fan stays on for longer than 30-40 minutes, something's up...