Well I'm in Sheffield and I used to have an orange a2...it wasn't me though! I've seen a few around and about Sheffield; one in the high green area, one around millhouses and ecclesall rd, and another on my commute to Barnsley. Have seen them all a few times... Think my old one ended up in Bolton though. I looked at another orange one also in Sheffield before I bought my original a2... There was a petrol in orange for sale recently at swifts (vw/audi specialist) in Sheffield, for those who might know it?
It is Jaipur Red, is hard to know about numbers as I guess that most were classed as red under the DVLA figures. It is a rare colour but there are probably more than you would think..they come up for sale fairly often, think there is a petrol model on autotrader at the moment; an SE with full cream/beige leather!
A distinctive colour, really suits the A2 I think...
Cheers
David