Hi Dave,
I have a very similar car to yours, its even a 1967 (actually mines better cos it's got wind up windows with 1/4 windows, haha). I got the car insured by Shannons (a popular insurer here that specializes in historic and interesting cars) two years ago. I was interviewed over the phone by an agent who really knew all about Mini's. He asked a couple of dozen questions regarding all the modifications etc. I was offered $15,000 full replacement cover on the spot which I accepted. If I wished they were happy to inspect the car to possibly increase the insurance value.
I had completely rebuilt the car mechanically ground up. Everything was new or restored however the body and interior were still original. Now the body and interior are fully restored I expect the value has increased dramatically.
I would imagine your car would be valued at $25,000 easily.
Hope this helps.
PS My car remains a Mini Deluxe, at least according to the badges
