Tiny black 'balls' on rotting wood. Some with the tops broken off showing hollow structure.
Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
Something which looks similar is Hypoxylon multiforme (Birch Woodwart) but not sure if it is the same as the black growth in your picture.
The wood was very rotten - best I can do is go back and look at the trees present - will try to go tomorrow. Thanks for your help so far :)
Lat/Lng: 51.0536, -0.7232
OS grid ref: SU895290