I'm sorry. I don't see Jayne 'correcting' Russell before first interviews as the way to go. It was the job of the PJ to detect and sort out any conflicts, not the T9.
I'd have the same issue if any other cohesive group got together and sorted out what they were going to say, in advance of interviews. I seem to remember at least one dog team did that, and produced statements that are worded nearly identically. Is that how it is supposed to work? Not for me.
And some of the very odd times we've got from staff. Should those staff members have got together in advance to work out the collective tale? Again, not for me.
I got assaulted once (very minor). The first thing the police did was to separate me from my partner so they got independent statements from both of us.
I don't agree that they were sorting out what they were going to say. They were doing their utmost to establish as accurately as possible their movements to and from their apartments to give to the police. The best way to to that was to pool their individual recollections. That can also result in someone having their memory jogged simply by something another person might say.
Any idea that they were colluding is daft IMO as they were doing this in front of a policeman - and immediately handed him the written timeline when they'd finished it - which suggests to me that he was waiting for it. Would you hand the evidence of your collusion on a plate to a policeman?
Being assaulted (sorry about that btw) is a completely different scenario and there is no comparison imo - unless the timeline was as important in your case as it was in this one.