Thank you for the replies so far. The MCA letter was said to have been sent out on the 2nd of April 2000 after a request. It is used in the book as an example and is a key part of the story. But the parts of the letter that would make it traceable are blanked out. I am not sure if I am able to post an image of the letter here. However if anyone wanted to type a few key words into a search engine lots of information regarding this will be available.
From my understanding I believe that a photoflash bomb is designed to explode behind the target area to allow good photographic conditions. How would this have worked with alleged underwater targets. And from what I have read the photoflash bomb would not be suitable for a low level flying exercise as the brilliance of the flash would have been detrimental to vision.
Also can anyone give a clue as to what type of UK plane would have been carrying such a bomb in 1974
The book states that a Harrier jets were also involved in the operation.