Bought my trophy on CC, it’s a crazy commission they are charging for offering zero protection imo.
At that level of commission I think they should attend and do a detailed independent assessment of the vehicle.
A few extra owners can be a good thing as they get older as each owner can do a little bit more to keep them pristine.
I’d always consider mileage, restoration and history between owners as many will just be collectors now with goals to make perfect.
I wouldn’t worry to much about the belts being done but be more concerned on the oil changes and history of the car.
Some of the service history may be lost but Google usually finds chat about the particular number and it’s history / usage.
As long as you allow for the belts in the asking price...