To prove my point, I found a couple from Eastenders, which come back completely no trace, no mot history, thus are highly likely screen cleared and thus never been issued by DVLA.
As I mentioned, sometimes it is a necessity to protect the owners reg number. However the other reason to use non assigned screen cleared plates, is if the character uses the same vehicle in many episodes, production doesn't have to keep multiple vehicles on standby. Therefore if the regular supplier of that vehicle hire isn't available, they can hire any matching similar aged, spec and colour vehicle and affix their characters reg on it. Granted some vehicles will display their actual reg numbers, for instance I ran a couple of Taxis from Corrie through the DVLA database, they are what they appear to be, so production will have likely bought them, as they are low value vehicles and cheaper to buy than rent. Also I suspect some vehicle suppliers these days will release the use of their reg to the production, so they can say "as used in Eastenders (or whatever)", as to a potential buyers it might make it more valuable come a future sale. As I said at the start, every production is different!
Edited by beardylondon, 02 April 2019 - 08:22 PM.
