I have a couple which were purchased from RegTransfer on cars in UK. Negotiated with them for ages, walked away once, but finially reached a price I was happy to pay.
Bought from DVLA OO08LAT, i.e. BLAT for my first Caterham (word is synonymous with brand). Its on retention, so if any of your new Caterham clients (with >2008 model) are looking change let me know.