Andy,
This has proved to be puzzling.
Most certainty a phrase I've never heard of and would expert otherwise.
One suggestion is that 'windae' is not referring to a window, instead it's related to the hurdy-gurdy being a musical instrument which requires to be 'hand cranked' - as in a 'windy (*wyndy*) box'.
Hmmm, not sure about that...
There is a debate about whether the lyrics are, 'in the windae boxes', or, 'all the windae boxes'. If the latter, makes more sense.
Anyway, as an aside, searching online, naturally came across references to Donavan's song, 'Hurdy Gurdy Man'.
One thing that leapt out was a mention Donavan being a Scottish singer-songwriter.
Dinnae think so... must be an error.
Part of the soundtrack from my youngling years, would surely have known if that was the case.
Duly check this out and stunned to find that he was born in Maryhill, Glasgow...
Alex, I was 'born and bred' in Maryhill...
If anyone would like to experience the sound of a hurdy gurdy, check this out:
Another revelation from my adventures...!