Tim,
Memories are flooding back to the days of young apprentices straight from school, who had been taught in metric, where around 1970 we used both measures in the electrical trade, 25mm = 1" etc etc. Cable was in metric and Brittish Imperial. Our fluorescent lamps started to shrink from 40 or 60 watt to 38 and 58 watt but told no loss of lumins, aye right, not! Oh and metric cable was a nightmare to work with in very cold conditions!
So yes, I agree with you completely, it was Brussels, or the French to blame. Now then, where is my foot rule???
Iain.