In reply to Neil Foster:
It may be that we’re closing in on the answer.
A couple of hours after posting this, I showed the photo to my partner and she suggested a crag without hesitation. She’s been ‘climbing’ (or do I mean belaying?) there for over 30 years, and the sign, or at least the message, seemed familiar to her….
And this morning, totally independently, a friend sent me a PM suggesting the very same venue.
One poster earlier in the thread has suggested the same venue so, though you can’t see it, I now have 3 independent suggestions of the same venue.
And that venue is……?