There's also Northumberland national park
http://www.dailymail.co.uk/travel/ar...-Sky-Park.html
But having been there last August it's not all that dark, comparable to say lower blue mountains around Linden. Pretty much anywhere in the Cairngorms was darker, and as good as say Hargraves lookout.
But go further away from Sydney and we have skies better than anything in the UK or Europe.
They have another problem too - a fair bit of smog makes it across the Atlantic from the US, meaning the sky is always slightly hazy by our standards. What the poms think is a nice blue day is nowhere near as clear as a piercing blue Australian country sky.