Thank you to Ben Owen for bringing this to our attention. Following the start of this thread I have made some changes to the entries we have for DVLA.
The main switchboard quoted in the OP (01792 782341) was at the top when one typed in
dvla
and it had a note to say that it was suitable for all enquiries. It is now at the bottom of the listings for DVLA and has a note to say that it is not for "customer" enquiries which should be made to the relevant 0300 number and that callers will be advised as such when they ring.
I have also amended the entries with 0300 numbers in so that they say that calls cost no more than a 01/02 call.