My question is why would you want to do this?
The normal and logical route is you receive your licence and then you change CAA which is quite a simple process.
After receiving your licence, you contact the Polish CAA informing them you will be transferring your licence to Irish CAA. You give them permission to release your details. You do the exact same to your medical provider so they can release your medical files. Then you fill out some paperwork from the Irish CAA website, send them some Euros and then everything is processed.