The Robin’s Pincushion or (Rose) Bedeguar Gall is always, I think, resolved in iSpot to (Diplolepsis rosae). I have, however, recently come across the key at https://www.british-galls.org.uk/bedeguar-keys.doc which seems to suggest that there are 17 possible species inhabiting the gall and that this number may increase (although also noting that some of the records may be doubtful.) See also British Plant Gall Society
Am I right in thinking that (D. rosae) is the gall causer and that all the others are either parasites on this species or are re-using the gall once its original occupants have departed?