Hi
If you intend to do a full energy upgrade you could do worse than appoint an energy advisor to carry out an energy audit on your property and advise on all matters relating to insulation, airtightness, boiler upgrades etc.
If you are only interested in airtightness, there are companies who supply the required materials to the irish market, siga and proclima are the brand names. if you contact these they should have lists of contractors who have completed their training courses. you can do a one day course with the suppliers of siga for €50, which may also be an option.