Where there's a will there's --always-- been a way in this case. You can't have a prosecuting witness in the stand who's committed fraud.
Exactly, but it's not just that Lookout. Remember, it was admitted that she had committed fraud and the trial judge misinformed the jury by telling them she had been cautioned for it. This, I think, is why the 2002 appeal court didn't take the point very seriously, because they took the view that the jury had already been given the worst case scenario regarding Julie Mugford's offending, a caution being the normal disposal for minor cheque offences, and since Julie Mugford's evidence depended on her believability, there was no prejudice to Jeremy Bamber.
The point they overlook is that there was a wider scope of considerations for the jury. It was not just whether she had committed dishonest acts in the past, but also whether she was entering into a deal with the police in which she was pressured to give certain evidence in return for various matters being dropped. When the judge misled the jury on this point, it was part of a narrative, which is continued by guilters on here, in which Julie Mugford's trial evidence is naively regarded as voluntary and spontaneous and the organic outcome of her own conscience, rather than something she was pressured into doing by Essex Police.