Call it a hub, bearing carrier, upright or swivel pin, on the Mini it's all the same thing. You'll need these (FAM2391=left, FAM2390=right) new hubs if you are converting from drums barkes to disc or if your old hubs will no longer support the bearings properly.
Rear hub nuts on the mini are sided as the threads are different. This is for the LEFT hand rear. This has a left handed thread. See NL611041 for the right hand nut.