It's the Gin Entrance. Try Caving Supplies for a copy of COPD if you're not too far away.
Ivy Green is about 30ft up the cliff & about (IIRC) a HVDiff. climb to get to it.
It was the scene of a very tragic accident in the late 80's.
A young lad from Eyam went missing, who was known to have an interest in caves in the area, but no known equipment to facilitate exploration.
When he'd been missing for some time, DCRO were tasked by the police to search all entrances that he could have crawled in, or fallen down in the area.
His remains were eventually found by some climbers about a year later, in Ivy Green Cave.
Lord knows how he'd got up there. He was some distance in, at a narrowing of the passage.
We inhabit an island made of coal, surrounded by a sea full of fish. How can we go wrong.......