So according to the police, whether or not a man commits a crime of voyeurism or indecent exposure depends entirely on what he claims to be thinking at the time. Is that really what the law says?
The law so often seems to give men the benefit of the doubt. In rape, for example, if the man can convincingly claim that he thought the woman was giving consent, then he's not guilty. Hence in France, where it seems to work the same way, dozens of men are claiming that they thought a drugged, unconscious woman gave her consent to having sex with them. Or, in the many cases we've seen of men sexually abusing children, or downloading images of child sexual abuse, we always hear a lot of guff about how the man was under an emotional strain and he's not really an abuser.
Looking at the voyeurism section of the Sexual Offences Act (2003), it says:
"A person commits an offence if—
(a)for the purpose of obtaining sexual gratification, he observes another person doing a private act, and
(b)he knows that the other person does not consent to being observed for his sexual gratification.`'
https://www.legislation.gov.uk/ukpga/2003/42/section/67
I suppose in the case of the changing room, it would all hinge on whether the individual can be shown to be observing the women undress for the purposes of his own sexual gratification. Though, frankly, I can't see any other reason why a man would want to use a women's changing room.