PMS and the law in the UK

From an ABC News (Australia) article:

1981:
Twenty-nine-year-old barmaid Sandie Craddock got off a murder charge after stabbing another worker to death when she pleaded diminished responsibility because of PMS. The judge accepted the argument that PMS was a mitigating factor in the incident because it turned Craddock "into a raging animal each month". A review of Craddock's diaries showed that each of her past 30 convictions and multiple suicide attempts occurred around the same time of her menstrual cycle. Craddock was found guilty of manslaughter, placed on probation and ordered to take progesterone treatment.

1981:
Christine English killed her married lover when she rammed him against a pole with her car after a fight. The court was told English had an aggravated form of PMS which contributed to a drop in blood sugar and an over-production of adrenalin before the incident. The court reduced the murder charge to manslaughter on grounds of diminished responsibility.

1988:
Twenty-year-old Anna Reynolds killed her mother by hitting her on the head with a hammer. At her trial, it was argued that she suffered from PMS, which led to the temporary loss of control and impairment, reducing her culpability. The murder charge was reduced to manslaugher.

Murder -> manslaughter would still be a conviction of sorts, albeit a lesser one. Still, at what point should charges be weakened? Should the courts then also consider some sort of testosterone poisoning?