Castrol seems like the only non local brand that supplies a full product range.Yeah I agree, Shell in Australia need to provide an API SP & Dexos1 rated, GTL based Shell Helix Ultra 5W30 and maybe even 0W20. They already have SHU 5W40 A3/B4 for the big toys.
To be honest I would prefer a GTL 5W20 over a GTL 0W20, as it would have lower Noack etc. But I realise most owners manuals now call for 0W20 as a sort of world spec., so a 0W20 would be much more useful to those who just want to follow the owners manual, which is most people.
However, SHU 5W30 C3 currently @ $28.60 is a steal.