IFT and D120A:
I appears that the "turned agent" was Eddie Chapman, known as Agent "ZigZag" by his MI5 handlers. Googling him produces an astounding story of double-dealing and duplicity, which has been the subject of both books and a film, titled "Triple Cross" in which he was played by Christopher Plummer.
It seems that the false information that he fed to his German secret service masters resulted in alterations to the V1 range settings, which displaced their actual impact points away from the densely populated areas of central London. Hence a number fell short, in more rural areas of Kent and surrounding regions. Over 1,400 fell in Kent alone, and these are plotted on a map which the "Kent Messenger" newspaper published in September 1944. It is reproduced in various books, etc, and I have a copy in a book titled "Kent at War" by Bob Ogley published by Froglets Publications and the KM Group.
Many of those that fell were shot down by AA fire and by fighter attacks, and as a 5 year old living in mid Kent with my mother, I can clearly remember the exciting sights of "doodlebugs" being pursued by RAF fighters with guns visibly and audibly blazing! To a 5 year old, all RAF fighters were "Spitfires", but now I suspect that Tempests and Mustangs were also involved. On one occasion while playing in our garden, a fighter came alongside a "pop-popping" V1 and seemed to flip it over, so it plunged to the ground - my mother rushed out into the garden and yanked me back indoors, just as it exploded with a frightening "whoompf". In our living-room the small panes of window glass all bulged suddenly inwards against their metal frames, and just as suddenly went back to normal, without cracking! It was a dramatic demonstration of the effects of blast, and of the surprisingly elastic properties of glass in certain circumstances.