You can get this yourself from your online account - see here:
Hope this helps.
EDIT: adding a link to more info: http://community.48months.ie/t5/Most-Popular-Questions/I-forgot-my-PIN-or-need-my-PUK/m-p/35067#U350...
It’s really easy to get your PUK.
You can get it via your account without the need to wait for us to reply.
Just go here https://www.48months.ie/profile/details and log into your account. Near the bottom of the page you will see your PUK waiting for you.