I've been told that the donor vehicle has been called in for an inspection. What does this mean?

An inspection is where the DVLA check that the donor car is using the plates legally, by comparing the car chassis number with its log book.

Whilst these checks do not happen very often they will slow down the transfer process by at least a week. This is primarily done for the safety of the person buying the plates. If it turns out that the car is stolen, then the DVLA can take the registration back, even after the transfer has been completed.