Galls at the bases of sedge stems.
No interactions present.
Interesting! I would have taken them for corms or something.
University of Edinburgh and Biodiversity Observatory (OU)
Yes, they do look like normal parts of a plant (probably another reason for being under-recorded), but are different when opened as there is a larval chamber (with or without a larva). If you have the Redfern & Shirley AIDGAP book of galls, Fig.176 on p.303 gives a handy line drawing of P. arenariae which is similar to the one here (but is found in a different habitat).
I have that key and looked it up. Will look for these in future. Thanks.
Lat/Lng: 50.9, -1.4
OS grid ref: SU4819