A cut lip probably comes under "minor, but not merely superficial, cuts of a sort probably requiring medical treatment (e.g. stitches", which is part of the Crown Prosecution Service's definition of 'Actual Bodily Harm':
http://www.cps.gov.uk...he_person/#P189_14382
So it seems likely that you friend will be facing a 'Section 47' charge.
It's unusual for a court not to grant bail for an alleged ABH offence. The rule is that bail must be granted unless there is a specific reason not to do so. For some offences (e.g. murder) the serious nature of the alleged offence provides sufficient grounds for a court to refuse bail, but that wouldn't apply to an ABH charge. So the court must have had another reason to refuse bail (which must have been given, in writing, to your friend). That could include the likelihood of a further offence being committed (which seems to be an unlikely reason for refusing bail) or the possibility of interference with witnesses. Bail could also be refused if your friend had failed to answer to bail in the past.
The sentencing guidelines for ABH (which a court must adhere to unless there are very exceptional circumstances) are on page 17 of this document:
http://www.sentencing...person_accessible.pdf
The sentences on that page refer to a first-time offender, convicted after a trial. Your friend's previous conviction will push the sentencing upwards, but an early guilty plea will have the opposite effect.
My guess is that your friend will just avoid a custodial sentence. If not, the sentence will pro