I can't help thinking if Scott Lomax wrote a book with an anonymous letter writer claiming JB had told him plausible reasons why he was innocent you would doubt the letter. That is fair enough but you have to be even handed, just because you choose to believe the letter writer is authentic doesn't make it so apart from in your opinion.
And I am only giving MY opinion Maggie, it's all I can post. I have already stated I didn't think much of the anonymous letter going into the book - it almost stopped me reading it - but there was information in the letter that made me believe the person who wrote it actually had spent time with Bamber.
The first being - he said Bamber gives nicknames to his supporters, negative ones - I know that's true.
And the 2nd being that Bamber speaks out loud when he is writing his letter, I know that's true too.
So for me it added credence to it.
But that's just my opinion, my opinion is all I can speak and just becuase I don't right IMO at the end of every post doesn't mean I am posting something other than my opinion.

I am sure people can tell I am not speaking for anyone else when I post a post.
Should a professional lawyer be making any kind of comments about a client? I would have thought it was highly unacceptable for him to voice his personal opinions in this way? 
He is entitled to his opinion. Doesn't matter if you like it or not, he spoke about his experiences with Bamber and his feelings of Bamber. He was a junior for the defence.