Given that Bach was (according to Wikipedia) divorced from his first wife with whom he had 6 children in 1970, the film JLS came out in 1973, and he married Lesley-Parish in 1977, I suspect that Hasel's timeline may be a little out.
Mind you, having read a lot of his books, I got the strong impression that the man is/was probably a bit of a nightmare to live with, and rather self centred.
Which doesn't stop him, so far as I can see, being a superb aviation writer.
Where I do agree with Hasel however was that his writing has always been at its best when he stuck to flying, rather than the more mystical stuff. But personally, I've always enjoyed both.
Bu66ered if I can see where the biography of a 2000 year old dead carpenter comes into the argument at-all however.
P