Here's what the judge has to go by in relation to the ABH offence:
http://sentencingcouncil.judiciary.gov.uk/docs/Assault_definitive_guideline_-_Crown_Court.pdf
See pages 11 to 14 but note that the sentences shown in the table at the foot of page 12 refer to a
first-time offender who has been convicted after a trial. (So heavier sentences can be applied to an offender, such as your ex, who has previous convictions).
The judge will have to consider the evidence about your injuries to decide whether they should be regarded as 'greater harm' or lesser harm' within the ABH category. I'd assume though that 'culpability' will be 'high' because of the breach of the non-molestation order.
So, looking at it from your ex's point of view, the 'best' that he could hope for would be that the judge sees it as a 'Category 2' offence (based upon 'low harm' but 'high culpability'). That means that, had he been a first-time offender, the judge would have to work from a 'starting point' of 26 weeks custody and then vary the sentence up or down, with a maximum possible sentence of 51 weeks. Given the information you've provided, it's likely that the judge would move the sentence up (and, since it's not a first time offence, the 51-week limit could be extended), so a sentence of 10 to 12 months imprisonment might be likely.
However if the judge rules that it's a Category 1 offence he must start from a sentence of 18 months and then work up or down from there. (If your ex was a first-time offender the judge would be constrained by a 3-year maximum sentence but, as he's not, the maximum sentence available would be 5 years). Again I think that he'd work up, perhaps with a sentence of around 2½ years.
So my guess is about 1 year if the judge rules that it's 'Category 2' or 2½ years if he rules that it's 'Category 1'. (The actual time served in prison would normally be half of the nominal sentence). It's likely that a custodial sentence would also be passed in relation to the breach of the non-molestation order but, as it would probably be made to run concurrently anyway, the actual length of it is largely irrelevant.