The problem with the "fake rape claim" argument is that it bears no relationship to what we know about the vast majority of cases. It's nice to respect that in theory, but the truth is that the vast majority of persons accused of rape are, in fact, rapists; furthermore, they very rarely come in for any punishment.
What AcidKing has said is basically irrelevant to cases like this, except for one wrinkle. The only thing that has changed in UK law, as I understand this, is that police now will interview the accused. This is pretty much how any other investigation goes; it's not clear to me why this is so remarkable in this case. So that basically leaves your standard questions for accused and defendants - how, when, or if to reveal one's story of innocence. Unfortunately the issue of whether or not to talk to the police is always going to be present, so any accused person should obtain legal advice how to proceed.
"Presumption of innocence" is a red herring here because it holds right through any potential trial. Nobody has ever believed that police investigating a complaint must investigate believing an accused is innocence - presumption of innocence describes
the reluctance of the state to pass an official verdict on the defendant. The principle does not say "thou shalt not investigate because that would be presuming guilt!" Of course the police presume guilt.
The whole kerfluffle reminds me of nothing so much as the bitching by some extreme right-wingers that honorable people were being put on trial for defensive gun use. I'm sorry, but society (and the deceased) has a compelling interest in making sure that a person who shoots another person defensively did so reasonably. If you can't present a good case, with the help of an attorney if need be, then you are naturally going to have a somewhat tougher time in a court of your peers. This doesn't come close to guaranteeing guilt, and it's not incompatible with the view that persons shouldn't be held accountable for crimes they didn't commit, that men shouldn't be jailed for rapes they didn't commit, or that private firearms ownership can be a good thing.
Honestly, if this was about
pedos under Big Ben we would all get it. Russell Brand gets it exactly right:
“It’s not for me to judge whether the claims against Lord Brittan are true, it’s for the police to investigate these claims as they continue to do so,” Watson said. “But I believe the people I’ve spoken to are sincere.”
“Well, I think it is for me to judge,” Brand counters, before launching into his dissection of the reported events.
Fuck "presumption of innocence" being used to silence people from using the brain they have to figure out tough questions like: Is it good to have sex with a woman you've only just met at a party and who is too drunk to say yes? no? barf?