There is actually an appeals procedure that they should have told you about. If it's on medical grounds, the process could become long and involved. If it;s after a drink/drive conviction there are now new rules requiring a DVLA medical before a licence can be returned. This sums it up: "If you want to appeal the decision, you will need to make a written application to your local Magistrates Court within 6 months of your licence being refused or revoked. You will need evidence, including medical evidence, to support your argument that the DVLA made the wrong decision and that you are fit to drive."