> My point is both that it's hard to tell,

Its not hard to tell for things like ".uk" or other serious suffixes.

It only (maybe) becomes hard(er) to tell for all the vanity ccTLDs that came along in the 2000s. But even then 10 seconds on WHOIS and Google should fix any doubt.

> about the reverence of `co.uk`

What are you on about ? Lots of other countries do it too. Japan is one example given already here, but there are dozens. It is very common practice for country tlds.