Only road distances for cars are in miles and yards. The British railways continue to use chains (which are not used for any other ordinary activity) and non-road traffic is often in metres or kilometres as appropriate.

Some of those "Metric martyr" types, the kind of people who think anything which changed after they were 35 is an abomination, but somehow anything which changed ten years before they were born has never been any other way, will vandalize legal stuff which uses (in their opinion) the wrong units. So if you put a (legal and reasonable) 1.5km distance sign on a cycle route, but some car driver who thinks sane units are fascism sees it, they might smash it to pieces which is annoying.

There has been a very gradual lean towards sanity, after all my mother was taught decimal currency because it was forthcoming when she was at school, her parents had used a non-decimal currency system. When I was a teenager I still had coins which, though they were treated as their modern decimal value, if you read their faces had a non-decimal value printed on them, because it's too expensive to replace the currency when you switch.

When I was a child I would buy a quarter pound of sweets. At the turn of the century I'd ask for, and receive, 100 grams or 200 grams as I felt, but most customers would use pounds (although legally they'd be served in grams). These days everybody else would likely also ask in grams. So it's changing, it's just very slow.