S1, E4: 4

Available on BritBox
Owen and Anna's relationship develops and he retracts his resignation much to Viv's surprise. Viv invites Crane over to her place. Anna eventually finds out that Viv is Crane's mistress, while Crane hires a private detective determined to find out who Anna has been seeing. Given a lead that it is the owner of a certain MG car, Crane tracks ownership to Owen. Initially they attack each others cars which leads to a fight outside Anna's Mum's house and them both being arrested by the police in front of Anna.