Likely sentence for ABH on a 15 year old?

[Ambie7]

My 15 year old son was assulted by his step-father in May this year. This assult resulted in thirteen stitches to his upper lip, internally and external, and a cracked loosened front tooth. There was also swelling and bleeding to the nose and many bumps on his head.
My husband, soon to be ex, had been drinking - about 3/4 of a bottle of vodka when he got into an argument with my son. He followed him to his room and punched him approx 4 or 5 times. Twich whilst my son was standing and the remainder when he was on the floor. All of this was witnessed by my 11 year old daughter :-(
He went to magistrates court in June but this was passed to crown court in July. A date of 4th August has been set for sentencing and a pre sentencing report has been requested.
On actual record my husband has no convictions even though previously he has been to court for ABH he was found not guilty - good solicitor :-(. So he has a "clean record" in court.
However he is know to police for previous incidents and it is logged on their intelligence system which apparently DOES get taken into account for a pre sentencing report??
What is the likely sentence he will receive given the above?

[loonytunes]

Seems that now, if you claim you are drunk, you will get awarded some cash from the public fund, an apology fron the court and a limo home. Unfortunately