Looks great! Small copy paste correction before you send it off.
I also previously wrote to the surgery about my topiramate prescription but have not received they have not responded.
I also previously wrote to the surgery about my topiramate prescription but they have not responded.
I would leave that out and not because of the tone of the additional information. The letter and its concerns are medical. I would keep it that way for now. You can bring other factors and circumstances in as appropriate if a back-and-forth correspondence develops. As written, your first letter is really concise and a strong plea. Don’t attach awkward bits and bobs to your aerodynamic masterpiece, they’ll just introduce drag. Less is more sometimes.