Overlapping insurance buying & selling cars?

[Justin Cyder]

Short of calling the insurers, I'm about to buy a new motor & so I'll have two for a while until the old one is sold. SORN isn't an option with no driveway or garage, so will it be easy enough to chuck a week or two's insurance on the new one prior to transferring the existing policy to the new wheels?

[Snowboy]

Yep.
Just call the insurance company.
They will charge you some money and do what you need.

[Evangelion]

Change from the old to the new one as you normelly would, then add the old one back on as a temporary addition. Cost is usually minimal.