The link from the OP says the "mileage verified by VOSA".
I'm not doubting the mileage is correct, but I'm intrigued over the VOSA bit, as I've not heard of this before.
What records would VOSA have to issue such a verification? They surely only have the MoT certificate figure to go by, which in turn is only taken from the odo reading, which could be clocked, or even a replacement speedo? (IIRC you could also voluntarily declare the mileage when taxing a vehicle, but again, it'd only be from the odo reading)
Edit: I hasten to add, I love the car..............