You may make images of Police personnel and equipment in public places/your own property, but only with permission... the permission bit might be a simple courtesy, but making images could be considered interference if the officers in question are doing something specific, so asking permission is not unreasonable imho

The trespass thing is correct. WPC should have not set foot in the property, although probable cause could have a bearing... he could have been arrested for obstruction. They could have written to him and asked him to attend his local nick, and failing that gone to collect him to attend an interview under caution.
As for the Police Staff camera operator, he never identified himself as a Police officer, so that much is blocks. A civilian volunteer, who regularly drives marked and unmarked vehicles, isn't impersonating a Police officer, so why would a camera operator be guilty of that?
I know someone similar to the bloke filming, and he has had run ins with the local Constabulary, emails deleted, threatened with arrest for arguing the toss over the behaviour of a couple of PCs and their treatment of him. Such people are always right, even when they're wrong. The best thing those two officers could do was drive away, but I wouldn't be at all surprised if that chap didn't find himself in court...