Dunno about the sheep, maybe grazing was allowed but I doubt it as the reports I have read suggested that the movements/passenger numbers through the Isle of Man at that time rivalled those through Croydon (wherever that is...).
I have an interest in this subject because about this time my mum used to be a hostess with Lancashire Airways whose duties involved weighing the pax and escorting them to their Rapide. But as the aircraft carrying capacity was much limited, the hostess never flew!