How do I know what wheels I have?

Hello all.
Having got a flat at the weekend, I need to look for a replacement spare. I found a set of wheels and tyres on ebay from John Craddock ltd, which are different from the ones I have all ready.
From the marks on the rims how can I tell which style of alloy wheel I have?
The spare, which had to be used is a steel wheel and will be going if I can get a 5th alloy.
Thanks

post some piccies and someone will probly be able to tell yer.