If anything, it's easier to "clock" a car with an electronic digital mileometer; As long as you've got the software you can just plug your laptop into the diagnostics port of the car and alter the mileage to suit your needs. The kit isn't cheap but id you're selling lots of cars it can soon pay for itself.

To clock an old-style mileometer you need to get inside the instrument pod and either change the speedo head entirely or wind back the clock manually.

My advice echoes that above: Get in touch with the company and ask them what the last recorded mileage was.

But let's not forget: A higher mileage car that has been looked after, maintained and serviced properly can be a better purchase than lower mileage car that has been neglected.