"The taximeter is the device that measures the charge."
No, that's adefinition, not the definition. The legal definition is what matters, and it was:
"“a device that works together with the signal generator to make
a measuring instrument; with the device measuring duration,
calculating distance on the basis of a signal delivered by the
distance signal generators; and calculating and displaying the
fare to be paid for a trip on the basis of the calculated distance
or the measured duration of the trip, or of both.” "
You should read the full judgement, the judge clearly was not happy with the black cab mobsters:
"These submissions are no more than an attempt, without clarity of wording or
thinking, to devise something which will cause the Uber system to fall foul of s11, in
the name of a purposive interpretation. It would also not avoid the problems to which
I have already referred, problems of a very considerable scale, for any driver or
operator using devices with which almost all cars are equipped, and sending the basic
information to the operator which any PHV operator would need for calculating fares
accurately and quickly. Would the use of a calculator fall foul of his interpretation,
whereas mental arithmetic might not? Would any degree of automation in the process
fall foul of their approach? "
His logic is concisely and clearly explained.