Loving this! Have only watched episode 1 so far but my theory is the Thing that was on the beach and is doing the killing and haunting is not a human thing/ghost but an Indian goddess - when it stood up on the beach it didn't have a human outline but seemed to unfurl a trunk!
So, elephant goddess, sent by Indian nanny to protect Young Tom that has stayed upstairs and will protect him for ever and ever by killing anyone who gets close to him.
Have recorded Episode 2 to watch in daylight!