I promised that I would get out to Hartsholme Park and finally I managed it.
The weather was pretty good so I could get away with 1/800 second or above, stopped down one stop and still keep the ISO within reasonable limits.
The first set of photographs I thought were great, but then I rechecked my settings and realised I had left the focus set to AF-S instead of AF-C. I have the centre button on my camera set to do a deep zoom, one quick click and I can check focus. Guess what? That spectacle sequence of herons in flight were all blurred.
I quickly changed my focus settings but the herons did not bank past me in the same that day. Oh well lesson learnt.