Thanks for all the comments folks, I appreciate them.
I generated an AVI of the bird frames and the wing beat doesn’t appear to match that of the flying foxes we see at lower altitudes.
This single frame shows the shadow of a much larger (or closer) object which might well be a flying fox?
I wonder how many AVI’s I have processed have frames with birds passing through but unless you are watching the screen, they tend to go unnoticed? There is something to be said for good old fashioned eyeball astronomy, eh Ron!
Cheers
Dennis