Vehicle licensing is a total nightmare. The horror stories I have heard are unbelieveable.
The only way to do it is to turn up, in person, with all documentation completed, wait in the queue of shady car dealers and refuse to leave the counter until you're sorted. Take some sandwiches if it's before lunch time.
To make matters worse, each VRO seems to make up their own rules so what works in one town won't work in another. Sometimes it'a just a paperwork exercise, sometimes they need to see the car. Sometimes they need to inspect the car but the inspector bloke is on holiday so it's hard luck for 3 weeks. If they need to see the car they'll tell you you can't drive it to them because it's not registered. You then get the car to them at vast expense and they say "yep, that's certainly a car", stamp some paperwork and job done.
Don't bother trying to phone them. All phone lines lead to a clueless bint in Swansea who'll tell you that VROs "aren't equipped to receive calls" what? no phones? Still on smoke signals, are we? Or have you been upgraded to semaphore already?
Arrrrgghh!
Good luck..
Kevin