Thanks everyone for the replies. Barry, it depends on how one would see the boundary of the house, the house and gardens abut against the outbuildings (i.e no fence) before the fields which are fenced, so I would argue that as long as it isn't put within a field then theoretically it would be in the grounds of the house. I'm sure power could temporarily be provided via an extension from the main outbuilding workshop. I will keep you all posted, and we shall see how long it takes before someone takes issue.
Regards, Richard