You could do a song from Mexborough :-)

Seriously, who is to know where songs come from. A lot of songs considered "Irish" were collected in England and vica versa.

Another example is tunes - Scan Tester was not known for his extensive travels from the South East of England but amoungst his tunes were "scottish" and "irish" tunes.

Abbots Broley Horn dancers now dance to an "American" tune so I understand.

You could start your set with "the blacksmith" and "Raggle Taggle Gypsies" as these were definitely both collected in England to prove a point then just do your normal set. I thought that you wrote (and performed) your one material anyway? If so your set will be "nominally english" as you are.

all the best.