'All the right notes, but not necessarily in the right order': musical resemblances over the Border

I discussed the similarities between two early Scottish tunes – the Skene manuscript’s ‘Pitt on your shirt on Sunday’ (circa 1630), and Londoner Daniel Wright’s ‘A Hilland lilt’ (1731) - with a London source published by the Scottish James Oswald – ‘Gie the mawking mair o’t’, dating from 1760 - and a number of Borders versions of ‘I saw my love come passing by me’. These have far more variations.
I compared the different sets of Borders variations, but what I found most interesting was the melodic and tonal structure of these tunes compared to the Skene and Wright sources in particular, and also to Oswald’s variations to a point.
I’m no stranger to the thrills of melodic comparisons, but in this instance the theme code system showed its weaknesses, even allowing for standardisation of rhythmic speed and key. By adopting Barnaby Brown’s piping concept of “with” or “away from” the tonic, I realised the obvious melodic similarities masked the fact, that the two groups of tunes began and ended at different points of the melody and tonal structure. The mystery as to whether they were originally related is clearly lost in the mists of time.