One or two did come forward when he was still alive; one in 2007; but they either could not face going to court or the CPS didn't think the evidence of the sole witness, the complainant, was strong enough to make a conviction probable. Remember that, until recently, it was essential in cases of rape and sexual assault, that the complainant's evidence be corroborated by some other evidence to support it.This absolute requirement has been removed in recent times but, regardless of that, the tendency is to look for such evidence before prosecuting.