Macfox, a possible option for you (though not ideal) would be to grab the Sydney guide data, rather than Adelaide - this means ABC2, SBS News plus all the normal channels 7, 10 etc would be in the same time zone. You could then shift all channels times by 30 minutes in MediaPortal configuration.
Only problem is if something different is showing in Adelaide than Sydney, though I'm not sure how often that happens.
I hoping we'd get a proper fix. I'm not sure how much traction James was getting over at oztivo. They offered to change the API, but got mixed reactions from competing grabbers, fixed on keeping the current API.
Please post and ask for this to be implemented, because this change should fix these problems and make it a lot easier for me to deal with the times coming from oztivo.