Havers' embarrassment when Lynley speaks to her about the case after just having come out of the shower, wearing nothing but a towel. She tries to be stoic throughout their conversation but ultimately gives up, at which point she tries to say Please Put Some Clothes On, but then changes her mind half-way and becomes even more embarrassed. Lynley understands exactly what's going on but finds it amusing anyway.
Not that Havers is generally prudish. She has a rather perverted sense of humour, as seen by her quip a few scenes later after a suspect has, er, exposed himself to the two of them:
Helen: Two female arsonists burnt down half a dozen semis between them. Something to do with firemen in...
Barbara: ...uniforms, yeah. Just sat back and waited for the hunks with their hoses. [they laugh]
[Lynley stares at them in disbelief]
Lynley visits Havers' new flat and Havers hurriedly tries to hide some drying knickers by stuffing them in a kitchen drawer. A few minutes later, Lynley decides to help her set the table, opens a kitchen drawer, and finds her knickers next to the cutlery.
As Lynley and Havers try to locate the caravan they're going to be sharing:
Lynley: Are you sure this isn't all a bit of a ruse, Havers? You couldn't find separate caravans?
When Lynley emerges from the caravan bathroom dripping wet in a towel, at the same time as Havers is about to go into the bathroom, dressed only in pajamas. They have to squeeze past each other in the half-meter-wide corridor, all the while trying to maintain a Stiff Upper Lip about the glaring UST.
Lynley is having dinner with Helen on a trip to London. After dinner:
Lynley: [checking his watch] I think I should be going. I don't want Havers to wait up. [Helen looks quizzically at him] I don't know if I've told you but we are sharing.
Helen: Sharing what?
Lynley: [Trying to be neutral] A caravan.
Lynley: In a holiday camp. [Helen begins to laugh and Lynley sinks his head in his hands in embarrassment].