Incidentally, if you're going to buy a spare from a third party you need to know:
1) how many holes for wheel bolts, usually 4 or 5.
2) the Pitch Circle Diameter, pcd, of the holes for bolts. That's how far from the centre of the wheel the holes are. There is no guarantee that the pcd is the same for two makes of car that have the same size wheels.
3) the diameter of the spare.
4) the width of the spare, usually a number like 5J.