Transferring a plate to yourself

What’s the process for transferring a reg plate to yourself?

The one on my race Alfa isn’t used so I thought I might stick it in the old Merc and just get a different one “for” the Alfa

Is there some guidance somewhere?

You have to put it "on retention" (fee £80) and then assign it to another vehicle, which will need to have a current MoT, there are other rules too such as the Alfa needing to have been continuously taxed or SORNed for the last 5 years, but if it's been SORNed more than 5 years, it has be taxed

Details on the DVLA website

Once on retention, you can keep it there as long as you like (I think). It used to be the case that the retention certificate had a time limit and you had to pay to renew each year, but they either stopped that, or decide that after many years on retention, you may never assign it and stop charging, not sure.

I think retention is for 10 years now.

Yes, could be. The plate I put on my white Coupe was bought many years ago at the same time as the plate on the other Coupe, but for many years I was paying £25 a year to keep it going before they changed to 10 years.

Thanks - gets complicated in that the Alfa is exempt as an historic vehicle