[CaptainZapp]

  Euro testing cycles are more generous, MPG figures are quoted in Imperial gallons

I have never seen a MPG notation anywhere in Europe (possibly in the UK, but certainly nowhere else).

Car efficiency is quoted by liters / 100 km just about everywhere around here.

Or am I missing something?

[to3m]

It is only in the UK. Nobody else uses miles, and the cutoff age for using gallons is something like 40-50 (and rising).