I had a search under various threads but am still a bit confused as far as upgrading goes.

I am planning on using Qantas points to upgrade on Australia-Europe discount coach -> business class one way. My actual trip is SYD-HEL/LED/TLL-SYD where I'd prefer to fly in business at least on long haul sections. Looking at QF website, I can only upgrade upto LHR for 50,000 points each way via Asia but not via North America. Is this true? After all, QF website states that permissable mileage is upto 15,000.

But if I want to use an OW award then I can't upgrade at all and have to take either an award flight or nothing. Is this correct?

What would be the best bet using QF miles to get to Europe and back while maximising miles i.e. earning base coach miles while upgrading with QF points?