Oh thank you JMB, that's very interesting! I didn't realise in my ignorance that such quarrying had gone on up there. Which demonstrates the importance of considering what has gone on at a place over time and not letting the 'obvious' era (obvious to your own interests at least) cloud your understanding / interpretation. I guess the 'track' also clearly joins that road at the bottom ('workway drove') that looks so obvious when you're actually sat on Knap Hill, so that makes a lot of sense too now.