A lot will depend on the prosecution's case.
(a) If they go after the substantial number of other babies who died when everyone agrees that LL could not have had anything to do with it, thus showing that the whole ward was hugely unsafe due to staffing/hygiene issues, then LL's conviction immediately becomes unsafe. Her defence team has always argued that she was only selected as a suspect when someone noticed that she was often on duty while a lot of babies were dying. Not a single autopsy at the time raised suspicions of murder. The idea that you have a really dangerous unit and simultaneously a woman who wants to murder a lot of babies would not have got to "beyond a reasonable doubt" status with any jury.
(b) However, if the case is that these managers should have stopped LL earlier, then the CPS are going to have a very hard time getting a conviction, because the accused will point to those same autopsy reports and say "We are an evidence-based organisation, nothing suggested that any murders took place". (One reason why LL's defence is so difficult is that there is no suggestion that they arrested "the wrong person". Either she murdered the babies, or nobody did. That doesn't happen often in the criminal justice system.)
As a backup, in the latter case, the managers could presumably call in the testimony of the independent experts who don't think that LL murdered anybody (i.e., arguing that they are not guilty of failing to stop LL because she didn't do anything). But of course that would put them at risk of argument (a)...