of course if for any reason they did proscute her she would be between a rock and a hard place the only way she could be found innocent would be by retracting her statement leaving her open to a perjury charge.
Well, while I am no expert, I would expect her to have a good shot at having any prosecution struck out as an abuse. There is no justification for the delay, firstly. Its not like the cops have just come into possession of evidence they have been lacking all along despite the exercise of due diligence. Furthermore, she gave her statements without being cautioned. She may also have testified without being properly advised about the right not to incriminate herself and on the strength of an understanding or even an explicit agreement with the DPP that she would face no charges. There is also the question whether she could receive a fair trial now, the case having been subjected to intense and widespread scrutiny over many years. A prosecution of her might also open a can of worms regarding the safety of Bamber's conviction as it might reveal undisclosed connivance between her and the cops which, had the jury known of it, might have affected the outcome.
For all these, and perhaps other, reasons I doubt very much whether we shall ever see her hauled back to court.