Can any legal bods chip in here?
Short answer to that Bowl is there may be a private law claim against the establishment for negligence. The victim would have to prove that the establishment had breached a duty of care to women by allowing someone who posed a risk into the changing room, and that it was reasonably foreseeable that they would commit the offence. It would depend on the specifics of course, but my instinct (and this is not my area of law) is that it could be very difficult to prove this. I expect there is case law on different situations where organisations/establishments have negligently "allowed" offences to take place but as I said this isn't my area of law and I haven't looked into it closely.
There may also be a claim for sex discrimination in that the establishment has treated a woman less favourably by putting her in the situation where she is assaulted. Again, I haven't looked at comparable case law on this.
For both these sorts of claim I think the difficulty is that the establishment is one removed from the person who committed the offence, so the victim would have to show that the actions of the establishment were negligent/discriminatory, which might be tricky (but not impossible).