How come Graham “Mr” Norton was the only presenter/commentator interviewed this evening? Excuse my ignorance, is he well known across Europe or is there some fascination with the UK?
Yes - many European broadcasters show The Graham Norton Show (SVT in Sweden do for instance) so he is recognised worldwide. It gets a conveyor belt of A-list Hollywood guests that many other equivalent chat shows across Europe simply don't (and that's why they buy it). And as others have said - the YouTube / Social reach is much wider than the UK.
In many ways Graham's the biggest 'name' associated with Eurovision across Europe other than former performers like Abba and Celine Dion. Not that many other national broadcasters have a commentator with as big a national reputation, presenting a major TV chat show, let alone an international one like Graham.
Whilst the UK may not always be thought of as taking the contest seriously as a country, the reality is that the BBC having Sir Terry, and then Graham as their national commentators is seen by other European broadcasters as the BBC taking the actual broadcast of the contest very seriously.
He's often been the only featured commentator on previous contests - such as when he had a confetti fired into his commentary booth in Copenhagen 2014 :