There are two ways I can suggest.
First, go to the groups tab along the banner at the top of the page and search for groups in Ireland.
Second, you can also look for a group of people who use the Medtronic Pump.
You can post a message in either/both of those groups stating that you are looking for Medtronic users in Ireland. You should be able to come up with any Tu folks in Ireland that use the Medtronic pump.
Hope that helps and good luck.
If you have a question or theory or success story or pics of your nattily decorated pump you'd like to share, I would suggest just tossing it up in the main thread and seeing what sort of responses you get! There's a lot of clever people from all over the world here and sometimes it's fun to hang out.
Only a fraction of members provide information on their location and pump model. In addition to brokenpoles suggestions, you can also do an advanced search for members looking for "minimed" users in Ireland. You will find there are 5, but at least you found 5.
And finally, you could go to the Medtronic/Minimed or Ireland groups and ask if there are other members.