So, I took my parents to the airport for their fourth attempt at getting to Australia today.
A-a-a-a-a-a-nd 6 hours later I went to the airport and brought them back. Flight cancelled.
Mum is a bit demoralised to say the least, so I sent her home (again) with a chilled bottle of cider and a couple of custard doughnuts. Small compensation but the least I could do.