There are various foreign exchange companies that you can do transfers with and if you do a forward exchange you can book a rate for a set period of time, I think 6 months. The company I have registered with, but not yet used, is hifx. I registered online and they then called me to confirm things and explain my options. What they said was I could tell them that I wanted to transfer x amount of money in x months time, I would get the rate booked now but would have to pay 10% of my funds as a deposit. When the time to transfer the money ifI still wasn't ready I could roll it over till the following month but I can't bring it forward. The other option is to take a gamble and hope you get a good rate. They don't charge for the transfer although your bank may charge you to transfer the money to hifx in the first place. The Australian branch is in Sydney and the website is
HiFX Inc : Foreign currency exchange specialists
I think that you are better to just pay the £3000 off on the cards if you already have £35000 savings and a well paid job. Surely it's better to just wipe it off rather than paying interest on the balance every month?