I know Insurance Companies have the access to get the information, if you up to it maybe phone your insurance company and tell them you want a quote on the car and then when they ask for the details give them the reg number they'll be able to pull all the details through and then ask for the VIN number for reference.
When I insured my car I didn't have the VIN at the time so gave them the License plate details and they gave me the VIN.
Its a long process but if you don't have any other alternative then it might work :thumbs: