Hermione Norris episode

There is this episode I still vividly remember seeing which featured Hermione Norris where she guest starred as a woman who came back to live in England from Africa with her husband and young son, however, the son was noticed to have mysterious bruising and it was initially suspected that it was two local bullies that were doing it, but then the police suspected the father when they saw him shouting at him for ditching school. In a later scene we see the mother getting drunk on her own and then the husband returns home and sees the house not tidied up after a dinner party the previous night, gets violent with her and starts pushing her around the house and punches her in the face. He then leaves the house, she leaves to go to the pub to get more drunk, goes missing on the way home, the husband phones the police the next morning when he notices her missing who then seems a completely different character than the violent one we saw previously, it's discovered that the son followed the mother and drove the car when he saw she was too drunk and crashed it by accident. Later at the hospital after she is found, it is revealed that it's the mother that bruises the son because she gets angry so much because she hates living back in England and there is no mention of the husband being abusive to her as it seemed to be some sort of red herring to make the audience think that the father beats the son after the police initially suspected him, but I find the whole thing rather strange, while it does indicate that domestic violence against children by their parents is un-acceptable, it more or less implies that domestic violence on women by their husbands is ok, does anyone else remember the episode I'm talking about and what did you think of it?