Yes I have it in writing from the memory clinic and I doubt the GP is going to contradict the consultant from the MC too. Good idea though to ask the GP to write his driving advice, thank you.If the memory clinic have said your father shouldn't drive, the GP will not contradict that so I don't think you need to worry about what his advice to your father will be. As you say, the difficulty would be if your dad decides to tell you otherwise as no doubt he'd be really annoyed if he thought the GP had spoken to you! Tricky.
Perhaps a letter would help? Do you have a letter with the diagnosis from the MC or could you get them to write one, confirming that he shouldn't drive? Or you could ask the GP to put his opinion in writing - tell him your dad keeps forgetting.