Andy Walsh said:The NPC (northern Pennine Club)Journal 1982 page 58 59 60 +61 has good photos of Colossus Pitch ion Large pot the original photos are probably in the NPC library in there base at Green Close near Clapham (yorkshire)
The photos show it done on Ladders!!(it was a long time ago) which is partly why no scaffold dig etc was done on a possible continuation10 m from the bottom of the pitch or dig in Pumpkin passage thankfully the NW and South East ends were dug with good results by others