Two different questions
People type “how long do trade plates take to arrive” when they are waiting on a set of plates from DVLA, or from whoever issues them for that trader. That is paperwork and a physical plate turning up. It is not a car moving.
A trade plate delivery is the movement. A driver collects a roadworthy car or van, drives it on plates OVM already carries and hands it over. How long that takes is a different page.
Plates arriving
The trader's own plates, issued for that business. Timing sits with the issuing office, not with OVM.
The movement
A driver, OVM plates, a legal car or van. That clock starts when the vehicle can actually be driven.
