By the way, Kenneth G. Wynn in Men of the Battle of Britain says that, after David got wounded on August 12, 1940, he was posted to RAF Debden on September 12 still as non-effective sick and returned to the squadron on September 27.
https://books.google.pl/books?id=3_x...%20RAF&f=false
They say he had his finger amputated, but why was he non-effective sick so long? Poor David, did he have any complications from his wound...?