OP
The answer, I found, is to use a service like currency.ie. I have used them a couple of times, no problems.
The most efficient way is to ask them for their australian bank details, and then do an online transfer from your australian bank to their australian bank, in A$.
If you try to do a transfer for a large amount from your australian bank to an Irish bank, you will hit limits. For example my bank in Australia allows up to A$100,000 in a domestic transfer, but A$5000 for international.
You can book a rate before you transfer, or I think they will also allow you a few days to watch the rate, then ask for the transfer to euro (or whatever).
D