Having fixed my previous problem of the MacBook Air not actually going to sleep I am now seeing battery life of no more than 2 hours. It also seems to take about 4 hours for the battery to charge up completely...very strange.
I am not in Safe Sleep mode instead running a custom "quick sleep" setting. My friend is running the MBA with "Better Battery" and is also seeing about 2 hours of battery life.
Any thoughts or ideas would be much appreciated.