Lookup with If else

Hi There,

I though I would be able to do until i got a brick wall.. Any help or directions are always apperciated!
I have large sheet with UK Car Reg. I need to identify which are over 2000 registered and call them new and everything else is old i.e.

LB50QWE -New
Z234GNV - OLD.

What I though to do was extract the number from 3 postion and compare, since old format was different but If I use the mid function, I also get value for OLD plate as well, any way I can do something rather than manually changing?

Hope its clear but let me know if anything hasn't been.