As above, the cost of putting the plate on retention for a year includes the transfer fee to a vehicle. If you're not the Purchaser then you must be the nominee. Definitely go to your local office. I did a recent transfer from retention to car and they did it there and then in about 5 minutes, new V5 turned up a week or so later. Much better than sending all the paperwork off and then getting "lost in the post" as seems to happen with a lot of DVLA post!