Quite right, when asked at the trial, Vanezis say's, "I have given it a lot of thought my Lord, at the end of the day i cannot be certain" I think if Vanezis had been called to WHF on the morning, he could probably had a better explanation?
Vanezis was a genius, he managed to hide from the defence and Jury all the cuts on Sheila and pass these off as blood trails and show all the one's Neville had in detail.
Vanezis' testimony was fact checked by Knight for the defence:
Vanezis cross-examination:
Q: Do you know Professor Knight who is sitting behind me?
A: I do now.
Q: A man of great experience isn't he?
A: Yes.
In other words he (Knight) will be scrutinising your every word.
Bamber was not convicted on Vanezis' trial testimony.