Around 10 years ago, looking up at the roof of the passage above the second pitch and the passage beyond, it looked then like a boulder roof of uninspiring stability, possibly particularly to people who had previously been in the meaningful-sized chamber above it.
There were certainly quite a few scars on the second pitch around then, resulting from debris from a gardened climb below the first pitch being chucked down the second for safety.
Given how active it is, I wouldn't have expected those scars to stay visible until now, but I could be quite wrong on that score, and I suppose some away from running water might have lasted a while.