I get chest infections all the time, and have been on a mixture of amoxicillin and predisalone everytime. From what I have read on both 'instruction' booklets in each pack, they mention nothing of alcohol, and from what I've been given advice from the doctor at uni, drining alcohol with those antibiotics is more of a myth, but lay of it to give your body time to recover from being ill.
Just complete the course, I sometimes forget and it doesn't go away completely lol, chest infections hang on for a while :P
Edit: having researched further, some (but very few) antibiotics do have some effects with alcohol, amoycillin isn't mentioned as having these.