The BBC won't generally comment on any HR matter, and this sounds very much like it's a HR matter if not a police one until there has been some sort of investigation, At most they'll generally confirm a complaint has been made and it's under investigation, they won't usually add any more information that isn't already known.
This is, I believe fairly standard practice for HR departments all over, as the company cannot do anything that is seen to be prejudicial to the HR investigation.
"the mother complained in May", that means there has been between 5 and 9 weeks since the complaint was made, that's not long for what could be a complicated complaint with lawyers and potential police involvement, especially at this time of year when there is a good chance the person being complained about may have other commitments or may not be available due to things like holidays, or other key personal may not be immediately available.
IIRC I've heard of cases of blatant gross misconduct in very simple instances where the employee of a private company has had the appointment with HR scheduled for 1-2 weeks after the event, simply because from memory the law requires the employee gets a chance to have representation and the companies have wanted to make sure they've done everything to not only the legally required standard, but best practice (so they avoid getting sued for unfair dismissal).
