Perhaps I should clarify a few details, just in case any of you were interested in doing the same thing... I originally purchased my foreign currency in mid-December 2010, using AMEX's FX4YOU via Westpac (which had the best rate I could find from anywhere - including other banks also using the FX4YOU system)... This was when the AUD was strongest against the GBP, and through this method, you can purchase the currency using BPAY (I used my CBA Gold Awards MasterCard - 0.5QFF/$1 for BPAY - better than nothing)! ... the transaction is treated as a normal purchase, so points are awarded and no cash advance interest or transaction fee is charged!
I also should correct - I meant to write 10c, not 10% (I'm so used to 10c being 10% of a dollar haha...)... If you want to see what I mean with the exchange rate, I purchased the GBP (and other currencies) on Dec 20, and sold back yesterday, where the exchange rate is about $0.10AUD in my favour per GBP, when compared to when I bought the cash.
Australian Dollar Exchange Rate Graph - British Pound - Historical Exchange Rates ... of course due to the difference in buy and sell rates, obviously I won't earn the full 10c, but still
I only used Travelex to convert the foreign cash back into Australian cash - so there was no credit card involvement with them at all - just took advantage of their offer for our employees of commission-free exchange (saved $24AUD - which was approx. 8% of the exchange value).
And to my points valuation - originally I only used to value them at 1-2c per point (which is what they are really worth when simply using to redeem for classic seat awards), however upon doing the maths and calculating the $$$ cost between the cheapest international (upgradable) economy ticket and the cost of a full price business class ticket, they would be worth 5.99c/ea - so I now use this valuation when deciding whether or not to pay surcharges etc