Just repeating what I was told and my personal experience, I did query this and that was the answer given, I don’t doubt that what you say is true. The point I was making is that GP’s are in the picture and the OP should not feel guilty about asking for a note which the practise will provide quite easily using their online system. If you re-read the OP you will see that he is in the same position as I was.
Not a criticism of you @jamesco, just getting a bit fed up of all the workload dumping by hospital colleagues, and the general assumption that the role of a GP is to do whatever anyone asks of them.