As we're putting it down to personal experience, and myself having lived in England
(of which I've spent near half of my life) and travelled extensively throughout Scotland, I know many many people who are aware of Europes monarchies; they just wouldn't be able to identify many royals on an indavidual basis. These people comprise of a number of varying occupations and have travelled and do travel frequently.
Again, I'm not suggesting
everybody (in the broader sense - especially the youth of today) realises or could name a royal house or indeed the name of a foreign European monarch but the general awareness that they exist is there.