I don't suppose the prosecution barrister is happy (and I don't understand why he was having a cosy chat with Rob and Bruce, he's not working for Rob), but presumably his duty is to make the best of it: will the jury think the evidence that Rob is a nasty piece of work is enough to justify Helen's claim that she only wielded the knife in self-defence fearing for her life?
Or maybe, she's guilty of wounding, but the judge will use the character stuff (Rob's and Helen's) to be lenient in sentencing?