Mystery moss?

I revisited the Mynydd Lliw concrete bases site again this afternoon with Alfie to take another look at the troublesome Didymodon. It implausibly looks more like icmadophilus than anything else, though I'm sure a simple solution will come eventually. I've collected a fresh sample to check...

Anyway, I also collected what looked like an odd Weissia, though with 14mm long setae and elongate unripe capsules I guess it's not. No doubt it's something obvious, but I'm tired and stumped! I guess it's one of the Pottiales and the cells are quite papillose. It was growing on damp gravelly spoil adjacent to the concrete bases, the main associate being Trichostomum crispulum. Hopefully someone can put me out of my misery...