Don't know about the flights but make sure your visa does not run out its I believe 89 days, I nearly did not bother getting a new visa in July as my current one would have run out the day after I was back in UK, the chap at passport control really scrutinized my visa and I am sure he was going to say something to me until I pointed out I had a new visa on another page!
Travel Republic had some good flight prices for September last week.