What was the end result? Did you fix the problem ... I have had a similar issue, but mine would stall while running ... get it towed and it runs the next day (for the most instances). Can't figure out what is going on.

need help with my 04 mini cooper s..took battery out of car to charge..now no crank..just a humming sound when turning key to start...towed to mechanic...car started up no problem.. mechanic says starter good.. battery good.. got mini back from mechanic..next day drove about 20 miles..played golf..then..same issue..same humming noise..towed to same mechanic. after unloading from tow truck..it started right up...mechanic checking electrical circuits now..anyone have any ideas??thanks for any help