[Joe]

Why, in this day and age, is it acceptable for an employer to "investigate" rumours of a consensual relationship between employees?

Because there's uncertainty around the circumstances in which they met (it has been suggested that the young lad was around 15 at the time) which of course begs the question of whether Schofield was genuinely helping him break into television, or whether there was an ulterior motive and had groomed him with the intention of having a relationship, once he became of age. Regardless, it was clearly inappropriate for a married man who was decades older to be having a relationship with someone who was young enough to be his son.

And the potential for an abuse of power is always worth investigating.