But wasn't the point of this evidence to show that the victim had consented
It cannot have been that - at least, not directly. The law is clear that the victim's previous sexual history cannot be introduced as evidence of consent. The Court of Appeal cannot change that. Their judgement is not yet available so I can't see their reasoning for allowing this evidence but it will be more nuanced than that. If it was directly about consent the prosecution would have gone to the Supreme Court who would have overturned the Court of Appeal.
The nearest you can get would be if the victim stated that she would never behave in a certain way, e.g. being unfaithful to her partner. If the defence can show that she has behaved in that way in the past it is clearly relevant as it shows that the victim's testimony is untruthful. If the victim gives evidence that is untrue it is a basic requirement of justice that the defence must be allowed to challenge it.
I would have thought that the suggestion of a reward would be particularly problematic when evidence is difficult to verify.
It is and, as I said above, the jury should take the question of rewards into account when determining how much weight to attach to evidence. Note that in this case at least one of the new witnesses was challenged about the reward. He denied being aware of the reward until just before the retrial and strongly denied that he had received any reward or that he would receive a reward in future. He also stated that he earned more in a year than the reward and that he would lose his job if he accepted the reward. The prosecution do not appear to have challenged these statements. Note also that in this case some verification was available in the form of text messages.
Is it the case that she challenged the submissions as evidence and denied sleeping with the other men etc that the wvidence given was false
The prosecution cross examined these witnesses. Judging from reports they seem to have focused on the question of whether or not these men received any rewards rather than challenging the basic truth of their statements. It appears that at least one of the men had text messages from the victim in which she appears to be indicating a desire to have sex with him (to put it mildly).
The evidence will not have come as a surprise to the prosecution. They knew what was coming. I find it telling that they did not use the victim's evidence to try and undermine these witnesses. That suggests to me that she was unable to deny their accounts.
On the "I believe" point, I too believe the victim's evidence which is that she has no recollection of what happened. She agreed with the experts that she had not consumed enough alcohol to induce memory loss and suggested that someone unknown (definitely not Evans) had spiked her drinks. There is no evidence to suggest that her drinks were spiked but the new evidence suggests she is prone to memory loss. So yes, I believe she has no recollection of events and therefore does not know whether or not she was raped.