Another species I’ve never heard of before today! Beautiful specimen. This is definitely in the “Cladina” or Cladina-like group of Cladonia. This doesn’t look really corticate, but it doesn’t look completely decorticate like other true Cladina, either. Can easily go through the list of well-branched Cladonia without squamules in the British Flora, and this is the only one that I can’t rule out. The photos on lastdragon appear to confirm the id nicely.