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

Really? I think it's a bit much. I mean, I know he won't serve the whole thing, but given the state of our prisons and, more importantly, the state of our CPS, I think I'd rather he did a community sentence and the money spent on incaceration went on something more productive. I think in this case a criminal record is probably a fairly hefty deterrent.
I'm going to see if I can find out why he got such a weighty sentence.

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.