Correct, you can quote metric or imperial. Most people (Tesco poll) quote imperial.
That needs updating. Tesco did their survey very soon after the change in the law in 2000.
Actually whenever metric is used it tends to be "just metres from the police station". Shows tend to quote miles, yards, feet, inches. This is true of BBC1, 2, 3, 4 ITV 1, 2, 3 and the Sky channels. Stuff like "Discovery Channel" is usually imperial.
Discovery Channel is mostly metric. When it isn't it's usually because the topic is featuring American society (e.g Forensic Detectives). The terrestrial channels, BBC in particular are showing signs of a move toward an increasing use of metric. I should know because I'm old enough to be able to compare it with 30 or more years ago.
