Confidence: It's likely to be this, but I can't be certain.
Notes: Differs from our usual British plant (H. aurantiaca subsp. carpathicola, Fox-and-Cubs) in its rhizomatous, not stoloniferous habit, longer leaves and phyllary measurements (the last not possible from the photograph of course). Interested to see this, having visited supposed sites for subsp. aurantiaca in Britain and finding only undoubted carpathicola. This looks like the real thing. Probably.