Confidence: It's likely to be this, but I can't be certain.
Notes: Having, at different times, provided the spurious ID of Ascocoryne (definitely withdrawn, see below) and also having then agreed with N. cinnabarina, I have been led back to this and looked it afresh. Conclusions: a) I must have been taking some kind of hallucinagen when I called it Ascocoryne; b) the form of growth doesn't seem to match Nectria cinnabarina, in which the perithecia are confined to small, cushion-like stromata. It does seem to be a Nectria, maybe N. coccinea, which can form less confined fruiting areas, as shown here, but there are numerous other species. I think ID to genus is safest.