Those injuries would seem to amount to 'GBH'.
See paragraphs 46 and 55 of this document (from the Crown Prosecution Service) to see the difference between ABH and GBH:
http://www.cps.gov.uk/legal/l_to_o/offences_ag ainst_the_person/
Whether a Section 20 charge ('GBH with intent') would be applicable depends upon the circumstances, not on the extent of the injuries. See paragraph 65 of that document for guidance.
This document states the sentences that judges must impose (other than in very exceptional circumstances). The tables (on pages 13, 15 and 17) assume that the defendant has been found guilty after a trial. (Knock a third off for an early guilty plea). They further assume that the defendant is a first-time offender. (Scale up for previous offences, especially if they involve violence):
http://www.sentencing-guidelines.gov.uk/docs/a ssault-against-the%20person.pdf
Chris