I didn't undestand why they said that diggers are on their own in the UK, and then in the next paragraph went on to talk about the UK's colour codes. It seemed like a contradiction.

I have a client who does groundworks and they always know when there's supposed to be something down there. You use the detectors to double check not as your only source. There could be something down there that's old and not on the registry or that HV power cable could be a few feet to the left of where it's supposed to be.

When you're the man taking a circular saw to the pavement and your boss is the one paying for the repairs, you check!