On the large wall near the canal opposite Sowerby Bridge cemetery is this Navelwort - Umbilicus rupestris. Next to it is a clever re-use of a stone gatepost, still with its former pintle on the side. The head of the gatepost now has a let-in iron hinge for a new gate. Nothing wasted then. Looks like Wall Rue is lurking in the shadows above the pintle.
I remember about 20 years ago Calderdale Council had a contractor pump in grout to all the drystone roadside walls from Todmorden to Eastwood. Every hole and cavity was filled in, presumably as a cheap way of stabilising them. Goodness knows how many mammals and birds etc were made homeless. With all this flooding we need to make sure our old walls aren't stabilised with similar methods but rebuilt properly. They are a great history book and home to allsorts.
Also Common Polypody-- Polypodium vulgare, in a wall at Mytholmroyd, showing the lovely orange sori underneath.