I see that the last post about this subject was back in Dec 2013..... well it is now only 2 weeks away and having read all 26 posts I find nobody has mentioned possible implications of the changes.
You cannot transfer any remaining tax to a new "keeper" and a refund will be made for any "FULL" remaining months when you notify DVLA of the change of keeper. Don't sell in the middle of the month then!
So what about the new keeper? If he/she buys the car in the middle of the month are they also going to loose out by taxing it mid month and only receiving 11 and half months tax? Or will your tax be for 365 days and not 12 months?
So how will it work for those who buy a car privately? Is this the end of private buying and selling of cars? You scan the local ad's for a car to then look at either in evening or weekend (if you are a working person) You cannot tax it either now, or under the new system without having insurance and MOT. If the sale of the car is in office hours, you could phone your insurance company and get cover over the phone, but that will not be uploaded to the Motor Insurers Database instantly and be available to DVLA for taxation. I asked my insurance company "How long does it take to show on the MID?" Their reply was... at least 24 hours or longer in some cases.
Remember also other recent changes.... if a vehicle you own (or keep) no longer has insurance you are obliged to declare it SORN... so it won't have any current tax. I always check
https://www.vehicleenquiry.service.gov.uk/ just before looking at any vehicle.
There are going to be some grey area's when buying a car after the 1st of October.... be careful.