@DrMopar
Which AAC codec are you using?
I'm using Monogram AAC. I'll try some of Kiwijunglist's suggestions as soon as I get the chance.
It seems that there are a few of us with this issue and presumably a number of users for whom it's not a problem. So we should be able to track down the common cause.
I know TV3 is the only one transmitting 1080i, perhaps it's something to do with the way they multiplex the sound which is why we're only having the problem on this one channel. But there must be something different in some of our setups that causes it to work correctly for some users but not others.
I'm in a weak reception area and get picture break up from time to time. (I'm trying to rectify this but that's another story.....) However this is mainly on TV1 (where I've never had sound sync issues) and when the sound does go out of sync on TV3 the picture is fine.
I have a pretty good signal ( not far from sugarloaf (CHCH) and Direct Line of sight)