He’s been done for Grievous Bodily Harm with Intent which is rather more serious than ‘assault’.
There’s three categories for sentencing, the first two of which involve the imposition of life-threatening and/or permanent injuries which, given the reported ‘minor’ injuries inflicted on the victim won’t apply in this case.
So I’d imagine he’ll be sentenced under Category 3 which is All other cases of really serious harm & All other cases of wounding for which custodial sentences of between 2 and 7 years are the guidelines. Instead of imprisonment suspended sentences and community orders can be given to ‘low-risk’ individuals.