I normally steer well clear of ballad tune origins as I am very much text-based when I have my researcher's cap on. Also what makes matters worse as far as revival renderings are concerned is the heavy muddying of the waters by the likes of Bert and Ewan. I use the word 'worse' as a researcher; with my singer's cap on I would be more inclined to use 'better'.

Regarding Bert's tune, somewhere in the dim and distant past I could easily just have assumed that Mike got his tune from Bert. Either way without serious research it would be foolish to put any store in a revival singer's version of anything regarding its relationship to earlier oral tradition.