I can see no Stan(d)l(e)y in the 1881 or earlier censuses that have any Manx connection - there is no Stanley family in the manx IGI except for that of Charles Stanley who was of a junior branch of the same Lancashire family as the earls of Derby - the Stanley's (and came to the Island for an administrative post), Thus I suspect your search for a deep manx background will be fruitless.
The name Stanley crops up in a number of English villages - one in Staffordshire I have seen referred to as Standley (the difference in pronunciation is slight)