You dont have an
ICAO licence because there is no such thing. Presumably you have an Australian licence. Australia (and almost every other country and supranational authority on Earth) is a member of the ICAO.
If you want to work in Europe, you will almost certainly need a JAA or (EASA) licence.
It is a very steep uphill struggle and you need to get yourself licenced in the area where you can be considered for work. There is a lot of very well qualified competition in the marketplace.
If you are Irish, and unless you have the right to live an work in other territories where you envisage a future requirement, then common sense would suggest you set out obtaining a licence that is required and issued in the EEC.
From the ICAO website:
ICAO does not issue any licences. Licences issued by ICAO Contracting States on the basis of Standards and Recommended Practices of Annex 1 – Personnel Licensing, are habitually called ICAO licences. This has led many to believe that there is a specific ICAO or international licence. The fact is that there is not one single international licence issued by ICAO or any other organization. States issue their own licences based on national regulations in conformity with Annex 1 specifications and validate licences issued by other Contracting States on the basis of bilateral or multilateral agreements or the fulfilment of nationally legislated requirements.