Ohme replied a couple of days ago saying they have passed my email to the accounts department to see if they can give me a rough estimate on price.
However, I have worked out that there is a much shorter route that the cable can take to the drive. I measured this route and the distance is just over 10m. So I assume I can just have a standard installation. The drive is against my house so there would be no pavements to go under or digging needed.