MyFavourite I think the problem for a lot of us is that it just seems so incredible as to be untrue - that not one senior manager knew anything. Because that would also mean not one junior member of staff (117 of whom did know something) ever got promoted at the BBC to become a senior manager. Esther Rantzen says she heard rumours while she was at the BBC. She was probably not much less of a VIP than Savile. Had she said something, I believe it would have been listened to.
Then we have the fact that the BBC prevented one of its own teams - can't remember off hand if it was Newsnight or Panorama - from showing a report that effectively would have blown the whistle on Savile around the time of his death. The only possible explanation is someone or some people were protecting the BBC and/or themselves from something they KNEW to be true - and that alone flies in the face of "senior managers knew nothing", even if that means they didn't know LATER, rather than at the time of these offences.
While these redacted memos have arisen, and Blackburn himself has released another statement, the Smith report confirms that no note was taken of this alleged interview with Cotton, Preston and Blackburn. This to my mind seems odd.
The trouble is that Smith herself said this culture of fear existed. That the stars were regarded as untouchable. Senior managers at BBC Manchester DID know about Hall and DID cover it up. It is therefore perfectly plausible that feel that a manager on the receipt of an allegation towards a big star would bury it rather than follow it up. And bury it by saying they had spoken to A7, he denied it, I felt it would be totally out of character and that's an end of it.
And that scenario would fit the current redacted memos and back Blackburn's claims that the BBC used to whitewash these events.
Even allowing for the fact that Blackburn was interviewed and 45 years later is sure he wasn't - and most of us would have trouble recalling a meeting about anything, even something like this that far on - the Police investigation into McAlpine regarded her claims as fantasy, what little we have seen of her diary tends to back that up, that her mother retracted the allegation, that another family member said that Savile's name was in the diary as an abuser but not Blackburn, that the family and police will not allow anyone to read the diary...
It's just all far too odd to be believable.