On the link you provided in the OP, clicked on a link for renewal of Irish passport. All the way down near the bottom of that page it stated the price was B12,000, including passport fee.
7. Either you or Key Visa will receive a telephone call or an e-mail from the Irish Consulate when your passport has arrived. Key Visa staff will then collect the passport and bring it back to Pattaya with the old one. At present it is taking 6 weeks to arrive back in Thailand.
PIECE OF MIND FOR ONLY 12,000 Thai baht inclusive of the passport fee.