Bill.... that is a good idea, moving the Barn Owl from time to time.
We have a heron visiting daily who is chased away by a pair of
resident sea gulls, they live up on the roof of the house. As soon as
....
I do not mind him visiting as my pond has stright sides and he cannot
wade in to it even he wanted to, the pond is 4 feet 6 ins deep.

This myth needs to die ;-)

Heron can take fish from the surface of the pond without getting their feet wet.
Someone posted a movie clip here a few months ago, the heron was
a few feet from the pond, dashed over and grabbed a fish near the surface
before the fish could react.

I have 3 foot vertical sides and its always worked for raccoons but recently
a heron took his toll. Bird net now and that has worked.