Bathsheba - depending at what point you dozed off -
Man in plot thinks his wife is cheating, so installs CCTV.
CCTV reveals his son smoking dope, and possibly engaging in sex with the fourteen-year-old over the road, and his wife meeting a group of strangers.
He heads home, and follows his wife and group to the town where they confront a man who has arranged to meet a fourteen-year-old girl - they film him and advise him that he will be reported to the police.
It turns out that the teenager in the family has been abused, and the culprit was not imprisoned - hence the wife's 'vigilante' action, and her confrontation of their son, advising him that he could be prosecuted or put on the Sex Offenders' Register because the girl he is with is under-age.
This explains why the man was in a therapy group, and why he drank for a time.
Last scene was him cracking a bad joke in the office, as it started, which implies that everything is resolved OK.
Future heads-up - as you know, the series is an inter-locked set of stories each featuring on character from the central scenario in the office - the manager has received a letter marked 'HM Prison' - no doubt all will be revealed.