There are several points to be borne in mind concerning any court case:
1) The legality of the initial search of Green's parliamentary office has not been tested in the courts.
(I suspect there is no wish to explore this fact by legal means and that measures are now in place to prevent a repetition)
2)Evidence obtained illegally may be ruled inadmissible by the court.
3)Potentially the police action could be regarded as gross and deliberate police misconduct.
4)The behaviour of Former Metropolitan Police Commissioner Sir Paul Stephenson is totally inexplicable unless he is deliberately interfering in politics. He is commenting on events 9 years ago that lead to no charges. At the least he is guilty of being in breach of enduring confidentiality. For this I would take away his pension on account of gross misbehaviour.
5)The initial whistle blower and his backup blabber are both guilty of the same offence and also one of them guilty of keeping records illegally.
The police may like the idea of turning themselves into paramilitary bully boys but they are subject to the same rules as the rest of us.
I view this affair as the police playing politics. For this reason, if no other, they need to be subject to court action. We supposedly live in a democracy, not a police state. The boundaries of acceptable police behaviour require to be crystal clear. That is far from the case at the moment.