Re John O Hazelgreen.
Joe,
As I said before I have been through all the OS maps of southern Scotland and the only Hazley Green I found was a couple of miles SW of Newton Stewart so it may be connected to the Garlies Stewarts.
If there is any fact in the song I'd say it surely must be after the Union. Even a lord couldn't wander leisurely across the lowlands in such a way for very many periods before that. The very fact that the ballad contains no conflict of any sort goes against the grain of the ballad stories. There is an old pack road going almost direct from Newton Stewart to Biggar and then Edinburgh.

I conjectured that a younger son of a laird would have been given some land of his own and perhaps be expected to marry into a wealthy family, but the pressure wouldn't have been so great on the younger son as on the eldest. The fact that the father went off to find the son's sweetheart and test her fidelity is perhaps a bit far-fetched to be of a real event? What do you think?

Needless to say don't even look at the Peter Buchan version unless you want a laugh!