I spent some time lying down in the sun ( just to make sure it was still shining ) all we have left is 10 birds in total in flight, sadly there is a nest high up in the roof of the steading with a nest of 4 unfledged chicks , they are getting fed by the others, I fear these may not fledge in time , keeping a aye on then though.
In the past when we have had late nests, the parents have stayed on into September to feed the young until they have fledged, then they leave. The young ones leave after a couple more weeks, though I have no idea if they have the strength to migrate the whole way.
Here, although ours went a few days ago, leaving only a couple of young birds, another 20 or so have appeared. I'm thinking they have come down from further north and will go south once they are all ready. It's still a week or so earlier than they usually leave, so they'll be OK.