Number plates, retention assigning new plate etc

There are some confusing bits of the DVLA site - it doesn't need an MOT, but if it hasn't got one it must have been taxed or SORNed continuously for five years, but if it's been on SORN for more than five years it has to be taxed, and therefore must have an MOT (unless it's exempt). It doesn't read well.

I'd just put it on a retention certificate. Fill in the form while it's still got MOT and Tax on it, and don't get rid of the car until you have the new paperwork - the DVLA sometimes want to inspect the vehicle. www.gov.uk/personalised-vehicle-registration-numbers/take-private-number-off

Once you have the new V5 and the retention certificate, DVLA will issue a replacement registration for the vehicle and that should be it, obviously you have to inform your insurance company, get new plates etc. Note that there is a need to renew the retention every ten years - it used to be every year. www.gov.uk/personalised-vehicle-registration-numbers/renew-private-number-certificate

Note that some registration numbers cannot be transferred. I think this was originally done so that people removing a potentially valuable old-style plate who got a replacement similar plate couldn't then make money out of selling that replacement plate. Your V5 will say if the registration is non-transferrable.

As far as I am aware, you can use it until the new paperwork turns up. What used to happen when I did this for work plates was that we'd quickly get the MOT certificate returned with the new registration on it, so we could then get new plates made and fitted ASAP. To date that, we also used to get a replacement tax disc. This was before you could do any of it on line.

We used to have these plates on work vehicles that were on the road every day. There was less ANPR around at the time - I think we used to make sure the drivers had copies of the various bits of paper in case they were pulled over. But we never had a problem with it.