Green DMM Walnut 11 (shiny, quite new) lost on 8th September. Probably in or near a route on Brown Slabs at Shepherd's (Borrowdale). Or less likely at Castle Rock (Yew Tree Climb) earlier in the day. Also missing an extender, which I suspect may have been left in the same place. They may still have red xmas tree tape on, but it falls off rather easily, so possibly not.
Wow! thank you for getting back to me. And thanks for the warning about the condition, I won't be using the carabiner again.
It was in perfect condition at the start of the climb, but I think must have happened cos I had to lower off from the belay (was cutting it too fine for the school run!) and leave my climbing companions to pull the ropes and start the route again without me.
So a lesson in what can happen when lowering off perhaps. And my climbing partners must have not seen it and left it there.