On-line transfer of ownership for UK registered vehicles
 

I have just discovered you can now transfer ownership or registered keeper as it is officially called of a UK registered vehicle on-line in minutes. It will obviously take a while to get the new V5 registration document but it could speed up the process for anyone selling one while overseas.
Whilst anyone registering a vehicle in their name in the UK does need an address there does not seem to be any residency check so this option should be open to anyone although getting insurance for overseas owners to use them in the UK does seem to be a problem.

https://www.gov.uk/sold-bought-vehicle

it was fast for me
 

I got a guy to do this when I picked up a new / old bike on a Tuesday I had the V5 in my hand Thursday morning in the post !