Thanks again for your support - my full itinery so far is:

LHR - CMB (Overland to) NRT - HAN (Overland to) SIN - MEL (Overland to) BNE - ZQN (Overland to) AKL - GIG - EZE (Overland to) LM - UIO - LHR

As far as I can tell, this itinery doesn't break the rules but I'm not completely au fait with how segments/stopovers etc work - what do people think?

One thing I've noticed over the past couple of days is that the LHR - CMB leg has become available by an extra day 4 months into the future (i.e. yesterday I could get the direct flight from July 11th and today it shows for July 12th) - does this sound probable? It seems odd that they would show all the connecting flights far into the future but not the direct one?