Justbusiness
Normally when you do a change of vehicle, this is arranged from a date/time. So for example, you could have said change would take place from 16:00 hours on 5/8/09. So you would be covered up to 15.59 for old car and from 16:00 on new. The garage would have Insurance for your new car up to the point where they hand over the keys. You could phone the Insurers first thing 8am if you have got the time of change over wrong, but I do believe that normally Insurers would cover your old up to point you picked up the new car. This would be on the condition that you had notified Insurers of the change of vehicle, but had just got the time wrong.
Huckster