what sentance are you likely to get for your third abh charge?

[littlemisszozo]

my friend has had 2 abh charges previously and was sentenced to 18 months and spent 4 months in prison. His license for the previous offence has ended and both have been spent, but now he has been charged with another abh which he claims was self defence as a result of a drunk, heated argument. Is he likely to go back to prison again for a longer time? What is the maximum?