My mini's been sitting on the drive for months and now my MR2 is all done up and my other half's porsche has had it's wide-body conversion, it's time to make the mini fit in!

It's a Q plate mini (apparently made up from parts!), but that doesn't bother me (obviously, I bought it didn't I?!) because I didn't buy it to sell it on. And it's in pretty good nick considering. I've already swapped the knackered MG Metro engine that was in it for a nice Cooper 1275 one...
Only thing is, I don't know how old it is (or most of it!) so I have no idea what mark it is. Can anyone on here help?
What distinguishing features should I be looking for? The most obvious one I can see is that it has the centre speedo... But that doesn't help me because I'm struggling to find info on what marks had that!!
If anyone can point me to a web site that explains the marks and the differences, or could explain a bit on here, I would much appreciate it.
Cheers (and nice to meet you all!)
Ruth
(Leicestershire)