The Enid Blyton Secret Series
The Secret Island - pt.3
S1 E3:
As the children take shelter in a secret hideout, they soon discover the identity of the ghost on the island to be a kind, old monk who has taken refuge. Aunt Harriet and Uncle Henry try somehow to prevent the authorities from closing in, having been alerted to their insidious plan by Lord Foggo, chairmen of the explorers club and mentor of Thaddeus.