Consider one of the arguments supporting Bishop's VC accomplishments from Hanging A Legend. Considerable invistigation seems to have gone into most VC's awarded to a recipient based on a single accomplishment; the King's highest decoration doesn't get handed out based on rumors. At the time that Bishop was awarded the VC, and this is the important part,
NO CONTROVERSY EXISTED. Controversy continued to not exist until a very amateur historian/docudramatist named Paul Cowan figured himself a brilliant researcher and decided to create a controversy. And why not; over seventy years later, it's hard to debunk a hypothesis with rapidly dwindling hard evidence.
If you said you hit a game-winning home run in little league yesterday and I wanted proof, you could probably find a scorecard or an eyewitness pretty easily. If I asked you twenty years later, you'd have little proof available and I can call you a liar all I want.
The possibilities suggested are definitely possibilities. I'm suggesting, however, that the King of England in 1917 likely had more information/evidence at his disposal than Paul Cowan did in the 1980s.
"Hanging A Legend", rather than proving that the raid did exist (and admits that proof probably doesn't exist), picks apart the flaws of Cowan's theories and "research" to the point where he becomes a pretty shabby authority. In other words, Cowan is unlikely to have hit a home run if he can't even swing a bat.