Hi Gerault,
I think you’re right with that, it might be a very strong K reaction which is reacting with the small amount of K in my C mixture (Milton Sterilising Fluid).
I went back to the site a few weeks ago and had a look for more of it. The chemical tests came up the same. The pycnidia “lichen” were abundant on a tree with a large amount of Alyxoria ochrolechia and are a similar colour to the pruina under UV. I wondered if it might be an odd form of Alyxoria ochrolechia with very few apothecia, abundant pycnidia and large quantities of pruina staining the thallus orange. The orange pycnidia patches do seem to grade into normal looking A. ochrolechia.
