Coming from NZ, the mountains of Scotland may not be as exciting for you as they are for flatlanders.
If you are around London and want to see things which are more difficult to come by down under, I would suggest a flight over Beachy Head and Kent, taking in any of these on the way: Bodiam, Hastings and Dover castles, the white cliffs at Dover (and Beachy head, of course), Canterbury Cathedral, Leeds castle, Rochester castle.
Another scenic trip in a similar vein would be to try to spot as many giant white horses and stoneage circles as you can from the air on the way to and from Compton Abbas, possibly going the long way home again over Bournemouth and the Needles & St. Catherine's point. The name would lead you to believe that the Cerne Abbas Giant (known for his large organ...) was close to Compton Abbas, but that is not the case, although he, too, would make a fun detour.
And, of course, flying into Duxford is always worth it for any aviation enthusiast.