The video claims that Bird was a professional police photographer - seems he wasn't, it was one of his roles. He was also involved in chemical fingerprinting but his main job was to prepare albums. He had two colleagues and it was 'the luck of the draw; as to which of them would be assigned what - they were on a rota. He described himself as 'the lowest of the low' as far as rank is concerned. The guy clearly was NOT a professional photographer, which makes it more likely that some of the pictures would have been unusable. I agree they shouldn't have been cut but the video is misleading! (And the guys voice is STILL dull!) 
It seems more reasonable to infer that PC Bird and the two unnamed officers were all "specialist photographers" and had obviously had training as police photographers. Whether you agree with the term "professional" or not is beside the point when using it as an excuse for poor exposure rate.
Think it through and it is absurd to believe that lots of pictures at a crime scene were "unusable" because the police sent some random officer with no training or experience.
It is also fairly obvious, when you consider it for more than a minute, that police photographers were not dashing to and from crime scenes all day. One of those roles where one is required on duty but often not called upon to do your "specialist" role. In fact it states this in the snippets that you posted.
The main role that they performed was obviously not the role they were employed to do and this is explicitly clear. They were photographers. They earned their living as photographers for the police. Sounds like a professional photographer to me.
