You started with the insults but from what NGB posted, it would seem that 'hearsay' is a legal term which refers to court evidence. So what is the relevance of it here? We're not in court! It's simply a way for you to reject anything that comes back from CAL to support Bird having only acted as photographer twice!
Understood? If you have understood that COLP didn't actually call Bird himself a 'specialist; it would have ended a LOT sooner!
Your failure to understand even the definition of hearsay doesn't bode well but here goes anyway.
In the COLP interviews Bird is not asked the direct question, "Are you a specialist photographer?" This has led you to erroneously believe that this is evidence that he isn't a specialist. The whole interview makes pretty clear that he is exactly that though. Why would they ask such a pointless question?
He does however concur with DS Young and Supt. McKay that crime scene photography is his specialist role. This role is referred to as a specialist role throughout the COLP interview which also refers to Bird's role as police photographer countless times. It is impossible to read the entire COLP interview without concluding that Bird is a specialist police crime scene photographer.
You are asking us to believe that Bird, despite concurring that his role as photographer was "his specialist role", several times, does not believe himself to be a specialist.
By inference Bird is a specialist and everyone can see this.
CAL does not herself claim that it was Bird's second ever time in the role. She paraphrases in such an otherwise needlessly ambiguous way, that the discerning reader (not you) immediately recognises possible intention to mislead. NGB, as a legal professional, will certainly recognise what I am talking about. Seemingly unnecessary caveats on a sentence are not even particularly subtle and immediately raise questions to the informed reader.
I am inclined to believe that CAL's caveat was not needless and that Bird had performed the role prior to being "engaged on the lab treatments".
"The Bamber case was his second as photographer while he was engaged on the lab treatment"
Why not,
1) "The Bamber case was only his second ever as photographer", or even,
2) "The Bamber case was his second as photographer since joining Essex Police."
If it was indeed only Bird's second time in the role then both of these sentences are more appropriate.
The caveat, in my view, is intended to mislead the reader into inferring 1 or 2 whilst avoiding saying so.