Actually you haven't. Its a Location Technology machine designed and made in Ireland (as you say). This was Eric Fosters company before he moved back to the U.K. and became Pulsepower Developments.
Eric was always good at repairing his old machines....none of this new attitude of some companies where at ten years old you can forget any help. The problem is though that there came a point where he just could not get the parts as they were no longer made. If you have the Deepscan version (VCO pinpointing, three settings, LO, coins to seven inches, MED coins in ground to 12 inches, HI coins in ground to sixteen inches. No drift/no retuning circuitry) it dates to around 1980. There were previous versions with the Mk III being sold in 1978-1979. So they are all really old.
I had a coil problem where sensitivity to copper remained the same but cupro-nickle fell right off. I had the coil replaced under its LIFETIME warranty (yes not just Tesoro) but the problem was that the plastic material had become slightly porous. Unfortunately the company (L.T.) closed and Eric himself has now retired so no hope there. Best to either look for one of his older detectors (Goldquest SS Mk 1 for the beach or MK II for land and beach) or a Deepstar though you will still face a repair problem if they fail unless Bill Crabtree is still keeping his hand in. Far better then most of the modern toy P.I.'s. If its a circuit problem the older Mk I green stemmed Beachscan circuit has Deepscan printed on it and they can be picked up fairly cheap which could provide componants but you will still need someone with a knowledge of pulse detectors. I suggest an appeal on the Finds P.I. Classroom forum. Someone might be able to help.
Brian