You are correct about Magistrates being compelled in terms of mandatory sentences, for example, have a blood alcohol reading above 0.05 and you have to lose your licence where in the past they had some discretion.
But they still have discretion in most offences, and if you sit in a Magistrates Court, watch how hard they treat driving offences, and in my view treat violence with a large degree of leniency.
We had a visiting Magistrate in our town that was particularly harsh on DUI, and very harsh on those trying to get their licence back. We later learned that their child was killed in a car crash. I argued that they should not be on the bench in traffic cases, but there was no such requirement and it seems the bias of some Magistrates is well known.
I do not envy them their job, but I would be tougher on violence, especially for repeat offenders. I am told our jails are full of traffic offenders, fine evaders, white collar crims and those who commit minor crimes under the influence of drugs. Not suggesting letting them off, but I consider violence especially on women to be more serious.