For 'Section 47 ('ABH') sentencing read page 12, et seq, here:
http://sentencingcoun...ine_-_Crown_Court.pdf
That's the actual document which judges must adhere to unless there are very exceptional circumstances. (Note: The sentences shown there refer to a first-time offender convicted after a trial. Sentencing can be reduced for an early guilty plea; in the case of custodial sentences that's usually by one third).
However, if you've not yet been charged you need to read this document (which the Crown Prosecution Service uses to assess the appropriate charge):
http://www.cps.gov.uk...s_against_the_person/
Compare the contents of paragraph 46 ('ABH') with those of paragraph 55 ('GBH'). Then look at paragraph 65, which shows the factors which can push 'GBH' up to 'GBH with intent'.
As I read it, there is a strong possibility that you'll be charged under 'Section 18' (GBH with intent). That's an extremely serious charge, which (if proved) would be likely to result in a lengthy custodial sentence. (For the sentences which apply to 'GBH' and 'GBH with intent', refer to the relevant paragraphs in my first link).
Chris