You can either contact the dr/clinic you went to who placed you on the list, or ask your gp to try to follow it up on your behalf. Sometimes there will be a nurse for the surgeon/clinical area who can be a good person to speak to as a follow up. Obviously if you have developed new symptoms or any new developments that might mean your need is greater than when you first went on the list, you should bring that up too. But usually it's just a case of waiting.