Wouldn't you just Adam and Eve it! Three days with the wildlife camera by the pond - nothing. This morning I didn't fix it up as I was contemplating moving the post which holds it in place to avoid the Sun glinting on the water. Just glanced across to the pond through the kitchen window (11.15 a.m.) and there was Mr(s) Grey Heron stood in the middle of the water. It spotted me almost immediately but I did manage a few shots as it beat a hasty retreat. They are somewhat grainy as the Canon was set to 1000 ISO and there was no time to adjust it.
I am sure that many birds have their own radar to detect the presence of a camera. There is little doubt it will be back so I must make sure the wildlife camera is ready at all times in future.