I had to replace my PTO shaft in mid 2011. My local dealer was able to get it shipped to Australia from the factory in Japan direct.
The part number at the time was: 142121100100 and the price then was 236.41 AUD.
If you need any more details or a copy of the parts list, please let me know. A friend and i rebuilt my PTO completely. If your still finding it hard to get the parts, please ask and i can talk to my local dealership or as a last resort i can order it for you and ship it to Ireland.
Parts for these tractors are hard to find here in Australia and i had a lot of trouble sourcing my PTO parts so im happy to help where i can.