Where can I find that? I'm inept when it comes to this kind of thing!
I'm quite sure they knew a good amount of what he was up to - probably not the ages of the children involved but definitely that he was skirting with legality (if not morality) of who he was getting involved with. I remember rumours that he was selling himself on a website, including very graphic photos and I managed to find said website and I am not great when it comes to the Internet etc so if I managed to find it - proving that rumour to be true - I'm sure they knew what he was up to in many ways.
My opinion is that if they truly know nothing, the best thing would be to stay quiet and deal with any accusations privately, rather than threatening people online. The person Lee Gaze is in a spat with has said 'I have the receipts' and is willing to take him on in court and I reckon you wouldn't do that unless you really, really had proof given the severity of Watkins crimes and how serious the nature of that kind of libel actually is.
ETA
@shellie what band was it??