In reply to Postmanpat:
Don't know answer, but in case you were thinking of asking DVLA for further details, don't bother as they apparently can not access their database without a registration number as I discovered last week.
If you give your insurer as much detail as you know, I would be surprised if they did not have the ability to find full car details bearing in mind that they have access to the Motor Insurance Database for fraud etc purposes. BTW, your access to the MID needs the third party Registration number at least for the online form. You could phone them direct though and see if they can do a check on partial details?