When I lived in Oxford, and the plant was making Rover cars, it was on the outskirts of Oxford in a place called Cowley and was known, unsurprisingly, as the Cowley plant.
It's still at Cowley although it is actually a couple of hundred yards further from Oxford than it was when it was a Rover plant. So how come BMW suddenly decided that Cowley was actually Oxford after all ! It reminds me of those estate agents where addresses like "Mayfair" or "Kensington" seem to cover much larger areas than they actually do in reality!
They do tours of the plant so you can go and watch the MINIs being built - it really is a fascinating trip to do. Folks on here often organise them so look out for one in the future and put your name down to join in.