Evidence civil case can the police be forced to release it?

If I remember correctly, two tapes are made of an interview. If what you are saying is correct, then both copies of the tape must have been altered. Again, if memory serves me right, you are allowed to choose which copy you keep and are given that copy when you leave the station - they must have been quick doctoring both copies! (I am going back 20 years though, so things have probably altered since then).