http://www.raccars.co.uk/news/article/2851/new-road-tax-rules-from-october?utm_source=raccars&utm_medium=email&utm_campaign=newsletter_20140818&utm_content=newsarticle

Its going to create some issues I fear.

Not being able to transfer the tax means that the new owner will need to tax the vehicle immediately - I don't know if that means that you will have to wait for the V5 in your name; or for the previous owner to cancel their tax; or double tax the vehicle if you can; or some of those; or neither??

As part of the current SORN, I believe, you need to actually return the tax disc if there is still some time to run on it. This would happen in instances where you don't want to have insurance on the vehicle. So I am not sure if you can actually buy a vehicle and SORN it if the previous owner has not returned their tax.

Kerching!