Its in Mrs Eaton's statements. Even she conceded at one point when she noticed Bamber didn't have any marks on his arms. Stop splitting hairs Roch. The family were unanimous from the off Bamber was responsible because the facts narrow the perp down to Bamber or Sheila. And since they were unable/unwilling to consider Sheila capable as far as they were concerned it had to be Bamber.
Two relatives conceded to Taff. Craftily, Ann misses out the info given by Taff, during the meeting, that resulted in the relatives reconsidering Sheila's culpability. I would argue this is because there is no information on earth that would deviate Ann from getting JB convicted. Hence her comment to police 'I can live with that'.