Let’s say the CPS decided to take someone to court for harassing the Inghams. That is one singular issue. That, legally, has nothing to do with what Chris did, even if the harassment against the Inghams has come about due to chris and his actions.
Whether or not he acted inappropriately, in another country and law system (where what he did was a federal offence) is irrelevant. For that to be considered that would have to be another charge, which won’t happen in the uk because what he did do is not technically illegal. Morally and ethically wrong sure, but not illegal at this moment in time.
Sure you could try mount a defence of ‘he is a bad person’ if you were accused of harassing him and call the witnesses in the world, but that doesn’t stop the fact that he also ‘is’ receiving harassment, which if the cps determine to be something trial worthy, would go to court.
Of course, if it then came out in court that they had in fact had been harassing other people, then a case and/or charges could be brought forward for that, evidence/cps depending. But that would be a separate case.