I have found my self in possession of a Renault Twingo.

The car is registered in the EU so I need to register it with the DVLA. As the car is over 10 years old, registered in the EU and a "normal" production vehicle this presents little problem (no SVA, type approval or similar, just tax, mot, insure and pay £55 to register and buy a set of plates)
The car cost me nothing, is not worth a lot, but I always liked the look of them (yes i know it's a bit Marmite) it's completely rust free, well spec-ed, and would make a nice little economical run around for the wife (and me when the cambelt goes or similar!).
Here's the snag; It needs to be insured to be registered, and as it doesn't have a number plate yet I need to insure it on the chassis number. The best I have been quoted is £500 3rd party for a year. Comparison sites quote me £210 Fully comp for a year if it had a numberplate (declared as EU import etc, surprised to see they would quote so happily actual, but that's off topic).
Cancellation fees after a month would see me get less than 50% of the £500 back. Does anyone here have any experience in importing / registering vehicles and thus have any better suggestions as to how I can achieve the insurance requirement?
Does anyone know on average how much a trade insurance policy costs?
Anyone know how a dealer registers a "new" car for a customer without them having insurance on it?
Anyone know how long a registration is likely to take (under 14 days and within the cooling off period??)
Long shot I know, but thanks in advance.
Ben