sec 18 intent

[commandopaul]

im on trial at the end of the month for section 18 with intent.
its a very long & complicated story but the jist of it being that for some reason 2 men wer making comments to a freind about giving me a beating, i left the club i was in "not drinking" & walikng through town came across one of the men, not knowing they had left the club also! the fella went to hit me but i hit him first, & broke his jaw.
as i walked around the corner there was the other stood with a group, he couldnt of known what had just happened!
upon seeing me he started being abusive & marching towards me bending down to break a bottle as he did so, i was backing up & backed into a wall at this time he was on me & went to hit me with the bottle, i some how deflected the bottle & he got it in his face cutting his lip quite badly.
i was defending myself one punch & deflection of the bottle but its very serious & alot of lies have been told by there freinds!
if found guilty what is my sentence likely to be?
i returned from afghanistan earlyer this yr & im due back in october. i have previouse for taking a car & theift over a decade ago when i was young & stupid!
i have a six yr military record that is exemplery "sorry if miss spelt"
i have a second job that i pay alot of tax on on my time off, basicly im trying to show that im a hard working normal person.
if iv thought about this once i have a million times & i cant see that i could of done anything different!?
i wasnt to know that i would cause these injurys but if the shoe was on the other foot would they have stopped!?
thank you for any replys.