The UK is not really metric - and if the Tories get their way when Brexit finally happens ( some time just after space legs I guess ) we'll move back to imperial measurements and give up on that new fangled metric sillyness.
I would call the UK "Hybrid Metric". For example, if you drive to a supermarket or other store, all the road signs will show Miles Per Hour and distances are in miles or yards etc. But as soon as you step into the Supermarket, everything is labelled with grams, kilograms, liters, milliliters, cemtimeters, meters (US spellings) and so on but if you ask someone how tall they are, the vast majority of people young or old will reply in feet and inches but will just as easily in the next sentence say they can or can't run 100 meters.
If Brexit arrives, to say we'll move back to entirely imperial measurements is ridiculous. That will never happen, that would make things far too inconvenient, almost as inconvenient as Fdev have made basic/Guardian/Thargoid material grinding. I've been playing since 2014 Beta and there's no doubt today's is the worst ever update, come on Frontier I know you you have your heads in next years "thing" but at least throw 1 bone not just crumbs.