All I can say, Heathrow Harry, is that:
1. Australia issued the Visa without question.
2. SQ only said I needed six months with less than 24 hours before departure.
3. They had four months to tell me.
4. Their Ts&Cs made zero reference to needing six months.
5. I had not originally intended to go out of the airport at SIN.
6. The reason I had the time to go out is because SQ made a stuff up of our booking and we had a 12 hour layover!
7. They acknowledged their mistake by issuing vouchers.
I thought I had done all that was required.