In my headcanon Tidmouth harbour had a USA tank from World War 2 until replaced by a Class 07 diesel in the 1970s when the USA tank was bought by the NWR; I also imagined the NWR buying Jinty when withdrawn by BR in 1964. Jinty helped build the Arlesburgh harbour 1964-67 and then took Duck's place at Tidmouth in 1967 when Duck started working the Arlesburgh line and harbour. Duck still did some shunting at Tidmouth in between trains at least until the NWR purchased the USA tank.
hm murdoch’s theme is quite appropriate for lady pulling the train, tho in the narration you said percy was in the middle while lady was in front and pub being dragged in the back. but thats not what is shown on screen. lady is in the middle in the vid not percy