The audio is always recorded and transcribed at a Crown Court. The transcriptions are a permanent record. This is why for example if a witness nods to affirm something they'll be asked to actually say "Yes" out loud if that's what they meant.
There is no objective public record of English trials.
Unsurprisingly if you request transcripts of a case in which someone was accused of raping a child, the witness statement from the child and associated examination by counsel may not be available to satisfy your "idle curiosity" whereas they might be available to the defence lawyer for the accused who is appealing the sentence based on something said in that part of the trial.