WAV, it's up to you what material you choose to add to your repertoire. However, most musicians are happy to acquire a good tune from any source, and always have been - there is no traditional justification for denying oneself a good tune because of its origin.

The tune you describe is known to far more English people than many "English" folk tunes.

The tune used for the National Anthem is probably German in origin.

The traditional repertoires of the British Isles are intermingled. I play a tune which Irish musicians recognise instantly as "The Cliff". I learned it from the playing of Bob McCann from Devon, who got it from his uncle. English or Irish? Another of Bob's family tunes, "Hot Punch" is also commonly found in Shetland. "Flowers of Edinburgh", "Bluebells of Scotland" and "Banks of the Dee" are traditional Morris tunes. English or Scottish? The answer is of course, both. The differences between English, Irish and Scottish traditional music lie more in the playing styles than the repertoire.

I can claim to have been indirectly responsible for introducing "Michael Turner's Waltz" to France. This tune is from the manuscript book of a Sussex fiddle player. I once played it in a session, and one of the musicians there learned it from me. He later moved to France, and introduced it into sessions there, where it is known as "Dave's Waltz". Recent research has identified the tune as being by Mozart, although it was probably an Austrian folk tune arranged by him.

Tunes migrate, and always have. To pretend otherwise, in the hope of preserving some kind of cultural purity, is futile. To deny yourself the pleasure of a good tune because of its origin is as fatuous as boycotting English country dancing because you don't like the word "ceilidh".