LOL.....I've never heard a seppo come up with a decent 'G'day' either....pommies can't do it either....its always 'Geeday'. fair dinkum?....you can't use fair dinkum?.....try it as a sentence of its own....the proper use of 'fair dinkum' is as a question...by itself...as an answer to almost anything anyone says to you.

In its sarcastic sense, its it can also be a term of derision to something you don't believe

Hitchy