I would ask the GP to look back at the handover letters from the oncologist when your RT was completed. The letter should set out whether you were to be monitored by urology or the GP. It may be that once they had tried to contact you a couple of times, they closed your file, in which case the GP will have to re-refer you. At this stage in your treatment, you should still be being seen by the hospital, even if only once a year and even if the appointment is with the clinical nurse specialist rather than a urologist ... don't let them fob you off.