A car of this age and mileage without a famous previous owner is likely to be worth around £25,000-£30,000, so any premium on top of that because of its history will depend on what documentation or evidence you can provide which proves the previous ownership, and also what someone is prepared to pay for it because of it. It is possible that this would increase its value by a few thousands pounds but there are no guarantees. We would suggest entering it into a classic car auction where you can include details about the previous owner, which will also mean it is seen by a wider audience.