Exmo, thanks for your help. I'm now looking at the following schedule:

cai-lhr-jnb-vfa//jnb-syd-mel-akl-syd-hnl-sfo-den-aus-ord-yyz-lhr-arn-hel-prg

I have a few questions.

1) I'm not sure about the number of flights I have in Europe as cai-lhr is a stop over. 2) How do the stop overs effect flights in the US?
3) Do I have to go back to Cai?
4) How can I work out the tax approx based on this flight plan?

Thanks