Court case- CPS v a driver that assaulted me last June

sentencing will take into account any relevant previous convictions, any failure to comply with previous community sentences, any personal mitigation as well as the harm caused by the offence in question and the man's culpability for this.
there are sentencing guidelines the magistrates have regard to (http://sentencingcouncil.judiciary.gov.uk/docs/Magistrates_Guidelines_including_update_1__2__3_4_5_web.pdf)
it sounds like he was convicted of common assault and a s.4(1) public order offence - you can look up the relevant guidelines and judge for yourself whether the sentence he got was excessive or lenient.

I was going to say. Don't feel any guilt about the fact that he's received a custodial sentence - it won't have been allowed to be brought up in court if he has previous similar convictions.

I find it unlikely that he would have received a custodial sentence if he hadn't received a community order in the past and it was found to have not stopped him.

Clearly the judge/magistrates had good reason to feel he needed banged up.