Yep, dating back to 1997-2000. When SM would have been 24-27/28. It’s worth remembering that at that time, the age of consent for males with another male was 18, not 16. That changed in 2000/2001 I believe. So this could relate to a relationship with a young male aged 16-17.
It was apparently reported and investigated in 2018. Dropped for lack of evidence.
But, there must be new developments for this to now lead to his sacking. Otherwise, SM may have grounds for unfair dismissal as the allegations and investigation in themselves would not be a sackable offence (as he was not charged and convicted). So either there is irrefutable evidence that has been presented or he’s admitted it.