If you intend to release it later on Pete I would make sure it does'nt see you with the food, assuming it is at the stage were it can feed itself. If you could use a blind like a sheet of cardboard to prevent it from seeing you providing the food, or replace the food while the owl is sleeping, otherwise if owls are like other raptors, it will become imprinted on humans and not only have no fear of them but could even become aggressive when hungry.
Where is Jasper when you need him?