I have often looked for this song also in the past w/ no success. There is a Makem Brothers and Tommy Makem website. I always thought to e-mail them from there w/ a request, but sad to say I never followed up. And if you get a chance to see them in concert, do so. They are very good.
Sorry I am not more help, but just put "Makem Brothers" in Yahoo! search and the site will come up.