My fave bit is the early morning scene where the guys leave the kids asleep in the cottage and exit the door.
The door is a '60s special large sheet of glass in the upper half and the door frame carries an 'Avon Lady' special bellpush not yet seen in 1940.
Iain McShane excels as the Sgt pilot and the final 'dogfight' extended sequence comes to mind every single VMC day entering the hold at BIG (and I'm serious!)
It must be the fp in me although farepayers not taxpayers now furnish the mortgage...