Odd One,
Many thanks for your well thought out reply, finally makes sense to me now.
Hmmm controlled airspace, now thats a small part I could never work out from the charts. About 10 years ago I did a few hrs dual in a Duchess ou of Newcastle upon Tyne to have a look at the way things are done over there but couldnt work out where contolled airspace was on the charts, apart from the TMA's.
Here in Oz, class C (controlled airspace) is like an upside down wedding cake, the steps get higher and higher as you go out. 50 nm out from a capital city airport means you can in some cases fly at 18,000 ft in class G airspace, and also track from nav aid to nav aid as listed on an IFR chart. Just be at a VFR level.
But i believe over there, controllled airspace goeas down quite low and follows tracks between navaids. (Airways). So how does one cross an airway if VFR and the airway goes quite low.