I did suspect R. repens, but this has the sepels totally reflexed, which R. r doesn't have.

TTBOMK

Well that would indicate bulbosus. Will you be going back? Can you excavate some leaves?

Have no fears, floral.

To quote Arnie "I'll be back"

As you say, floral, it has to be bulbosus.

I was/am so surprised to see them growing in such conditions and looking so healthy.

I'll need to excavate a bit deeper and find out how deep the crown is. There can't be much in the way of organics or moisture.

I was on top of a cliff today and had a good look at the buttercups. I think they were the same as yours. The harsh conditions had made them prostrate but the leaves were visible and the sepals fully reflexed. Seems to be a very adaptable species.

I noticed there is dandelion and ragwort in your picture so clearly there's moisture below the surface.