Aren`t Creswell Crags just over the border, in Nottinghamshire?
As a young lad, in the `60`s, I remember going on a school field-trip to Derbyshire. As we were eating our lunch in Thor`s cave, one of the kids pointed up at the wall and said, "look, a cave painting!" I couldn`t make anything out, but several others, including the teacher, apparently did. I remember thinking, at the time, that this should be reported. I`ve not been back, since. Perhaps I should go and take another look.
baz