what do we think of this rate/risk.
I only have very big picture opinion, not much depth of knowledge about bonds.

Infratil bonds (closed May2011) were 8.5%
Z Energy bonds are 7.25%

I don't see much risk in the failure of petrol station business.
I see the biggest risk over Z Energy as a gradual move away from petrol stations when oil runs out (10 or 30 years away?). Maybe petrol stations will become electric car plug-in points, or Hydrogen fuel cell outlets, or just new new "corner dairies", but if cars disappear and everyone uses electric buses or monorails (or bicycles), petrol stations will suffer the same problem that Bookshops are suffering in the face of internet books.