No comment wouldn't help her at all since the right to remain silent has essentially been abolished in the UK "it may harm your defence if you do not mention when questioned something which you later rely on in court."
Not so. It's just a warning that, in some circumstances, adverse inferences may be drawn from your silence. According to Wikipedia:
"Adverse inferences may be drawn in certain circumstances where before or on being charged, the accused:
- fails to mention any fact which he later relies upon and which in the circumstances at the time the accused could reasonably be expected to mention;
- fails to give evidence at trial or answer any question;
- fails to account on arrest for objects, substances or marks on his person, clothing or footwear, in his possession, or in the place where he is arrested; or
-fails to account on arrest for his presence at a place.
Where inferences may be drawn from silence, the court must direct the jury as to the limits to the inferences which may properly be drawn from silence. There may be no conviction based wholly on silence. Further it is questionable whether a conviction based mainly on silence would be compatible with the European Convention on Human Rights."
The issue in Helen's case is whether she could reasonably be expected to answer the questions. Her lawyer will presumably say that she was 34 weeks pregnant, traumatised, desperately worried about her child, and in particular suffering from the severe psychiatric damage inflicted by Rob, so it was entirely reasonable for her not to answer questions.