Collected from a group of Garden Snails (Cornu aspersum) 20/10/2021 at St Nicks Nature Reserve in York (VC62, SE6151). I think this is most likely Riccardoella (Riccardoella) limacum - it's noticably different from the Riccardoella oudemansi that I have collected from both slugs and snails. The hairs on the back are much longer and thinner, which indicates it's likely to be limacum - but any confirmation appreciated!