Current access agreement is (IIRC) to phone Lobby Farm beforehand to arrange getting the Old Ash key, their contact details should be on the DCA website. The Barnatt-Worthington survey for both mines is available here: https://pdmhs.co.uk/MiningHistory/Bulletin%2016-3%20-%20Using%20Coal%20to%20Mine%20Lead%20-%20Firesetting%20at%20Peak%20District%20Mines.pdf
I'd be interested to know if the latex lady is still there in Lords and Ladies....