Looking at the main Dr Who forum, it seems his antics have also been an "open secret" in fan circles for a long time. Someone saying he stopped getting invited to fan conventions as he acted like a predator at them .
Another said - "Noel was very much what you would call at the time a ‘LAD’ on and off set and like many men that age, life was all about the drink and the women. The production team had to put a notice out to the female production staff and even hotel staff to not except or encourage his advances during the frist and second series.
Looks like his behaviour and conduct has escalated over time, so this stuff coming to light was only a matter of time."
Another said - "Noel was very much what you would call at the time a ‘LAD’ on and off set and like many men that age, life was all about the drink and the women. The production team had to put a notice out to the female production staff and even hotel staff to not except or encourage his advances during the frist and second series.
Looks like his behaviour and conduct has escalated over time, so this stuff coming to light was only a matter of time."