I think that two things are going on here:

[1] The copying. Is the person who does the copying economically resident in the UK?

[2] The transmitting. Is the person who does the transmitting economically resident in the UK?

It is almost impossible to work out where the transmitting chain crosses national boundaries.

I used some music clips on a business website to illustrate the concept "Every cloud has a silver lining". I had to remove "Hi ho silver lining" but by negotiation, was able to keep "The clouds will soon roll by", "Happy days are here again", "Painting the clouds with sunshine"and "The sun has got its hat on" which were out of copyright.