I was reading about this stone in ‘Holy Wells of the Bath and Bristol Region’ by Phil Quinn. It’s my pure speculation, but it could be relevant that the stone was situated by the pool – that is, perhaps the pool was the original place of veneration. The pool (now filled in) and stone were to the north-east of the church. I do realise they have to be in some direction, but it did remind me of the Rudstone Monolith which is also to the north of its church. And if it’s a genuine standing stone, it can hardly be a coincidence that they chose to build the church next to it, recognising its importance in some way.