This page (https://www.ukclimbing.com/logbook/crags/callow_rocks-17502) describes the location. I live nearby and decided to take a look. But try as I might, I couldn't find it. I went twice, second time armed with my mobile phone sat nav GPS. At the very spot described, there's a fence to the working quarry. Unless I've got something very wrong, its either been spirited away to crag heaven or been eaten by the working quarry.
Is there anyone out there who knows if it still exists?
Callow Rocks