very long shot - -!!
This was a song local to the Tarbert area of Harris (Hebrides) in the late '60s to mid-'70s - tho' it may have been sung for a while after?
Amhuinnsuidhe Castle's new owner (1968-1976) Sir Hereward the Ladwake did not like the fact that the public road went right past the front door of his castle and proposed a bypass in order to maintain his privacy. In the event the bypass did not happen - think the Free Church of Scotland argued against permission being granted as the road was only access to a village farther on - but the song 'Last Vango in Harris' appeared (Vango is a well known make of backpacker's tent) and the only part I've heard is the first couple of lines:

'Pardon me boy, is this the Amhuinnsuidhe bypass?
Is Sir Hereward in, I've heard a lot about him...'

(tune is Chatanooga Choo Choo!)

I am hoping that there may be remnants of the song floating around in a few memories, that we can fit together a jigsaw of phrases and reconstruct the lyrics?
Fingers tightly crossed - -!!!!