[amclennon]

I would envision such a system to be based purely on odometer reading since that might be easiest from a logistics perspective

[Ekaros]

One idea that comes to mind that would be relatively simple sanity check is data from average speed cameras that UK has. Somewhat dystopian solution would actually be also track distance driven between these. And add it together over the measuring period.

[blibble]

that would be good, but UK politicians are very interested in pricing usage based on time of day

which doesn't work if you only check the odometer once/year