Just a technical reply on the "d minor" point.
In folk music (whether English/Irish/Scottish) we tend to be a bit loose about the use of the word "minor". Loose and usually incorrect.
I have to keep reminding myself of these things. We often talk of E minor and A minor, when in fact we mean E dorian and A dorian; I know, it's easy to do. Though I've mostly stopped my self doing it these days, I still get people in sessions and band members referring to minors when they mean dorian. No wonder guitar players get so mixed up and new ones get things wrong.
This is true of the vast majority of trad tunes that we play that sound a bit "minor".
I could try go into all the technicalities, but I'm not the best person to do that. This is a pretty good page dealing with the whole modal thing:
http://slowplayers.org/modes-keys/
btw. You could replace every mention of Irish or ITM (Irish traditional music ... not a contraction I'm too fond of) with "English" or "English traditional music" and every word of the article is still correct.
So, what you are playing in is D dorian not D minor, confirmed by the fact you can play the tune on a C whistle ie. F natural, but also B natural not flat as it would be in D minor.
PS. someone often comes in with the argument that a particular tune simply leaves out the B/B♭ so the tune could be D minor or dorian. My point would be that the starting point for most of the "minor" tunes in the tradition is dorian, and also that just because a version (or manuscript) of the tune leaves out the B doesn't mean that every other one does.
* I did go into a load of Melodeon based musings, but this is a whistle forum.
