American Express Currency Exchange - All American Express FX4You online transactions made entering the promotional code UOW between the 27th February and 31st December 2015 will receive a preferred exchange rate.
I found that even their normal exchange rate is better than Travelex. The site is a little bit fiddly, but worth it if you are going overseas soon. Also convenient since they send the money to most Post Offices and you don't have to go to a foreign exchange vendor.
HOW TO:
For some reason, when you try to order the first line in 'Choose your product' is buggy, you have to go to the second line and choose Foreign Cash and then choose the currency you want.
And then when you add the promo code UOW, it won't automatically update the rate. Click continue and then click back, then the rate should be updated.
Happy travels!
You may want to add in the comments that this is only for $500 or more.