Leucoagaricus nympharum -- possibly!

On a visit to Aberglasney recently I spotted this beneath a plant in the 'Nympharium', a garden within some old rooms of the house which has tender plants/orchids etc.  I did not collect it so unsure what it is.  In Buczacki there is Leucoagaricus nympharum which seems OK -- gills white tending to pale reddish.  It is curious that this L.nympharum was found in the Nympharium (called after gardens in Italy created in old buildings ---- I think) !