Pointless aeronautical trivia and digressions off topic? Here I am.

Sorry, I was away.
I was told that the name 'Dylan' was changed because the American pilots couldn't cope with the 'oddity' of the name during one of the joint operations US and British forces were on... Bit odd given the name of one of the US' most popular singers, and it sounds highly suspicious to me. However, remember, wherever you are, all foreigners are stupid, right.
The fairground roundabout pre-dates the road intersection, so I'd assume the name transferred from the entertainment one to the one that's just entertaining watching N Americans try. The Met(ropolotan Police Force) refer(red) to London's orbital motorway at the Magic Roundabout, given how unfunny it was.
As to the origin of the programme, as has been said, it's a slightly weird
French TV show that was hugely successful in the UK. While not many (any?) kids today would have heard of it, it was universally recognisable in its time in the UK, and the characters were used as models for many people's friends.
"And Zebedee said 'Time for bed'." is still a widely known catchphrase among many of a certain age, and being over 18, the alternate implication is often much enjoyed.
Regards,