Would prefer to turn up to Peru with cash rather than having to try and exchange once I arrive, or alternatively pay the ATM transaction fees.
I would suggest that it is easier to just get your soles in Peru. I had no trouble obtaining currency there as I required it in the various major cities. You are unlikely to find a place in Sydney as it isn't a standard convertible currency and even if you do, the exchange rate is likely to be very bad (much worse than a few dollars of ATM fees). about 8 years ago