I do know that they are a local homeless charity and does seem they provide hostels/living support. Recently surveyed and it's still not clear from the outside what it is. 

Their donate food web page (https://stonepillow.org.uk/donate-food/) does list the building on this road as a hostel, so I've tagged it as such and put a note on the building for other mappers in future that it's not easy to tell.