Uk legal procedure question

[Samun]

Hello,
I am a law student from Poland an I am writing an article about video and audio evidence in civil procedures around the world.
Therefor I need help and an answer to the following questions, because I have no data regarding the UK:
1. What are the rules of making such an evidence?
2. What kind of evidence is prohibited???? (right to privacy? state and company secrets? personal image?)
3. Any important cases in the matter?
Could any one point me a resource where I could get information about this topic?

I will be very grateful for any information!