How to add to existing letter?

I asked my gp to do a letter for me(reusing a good old letter) to help with my pip and she told me She won’t do it again as they don’t have to but I’ll do it on this last occassion.

She’s reusing the template which covers care activities so no issues there hopefully.

Last time I was given points for walking descriptor due to my very old cfs diagnosis letter and my answers with not much else. I was worried this might not be enough this time do asked my doc to add a line or two about how my cfs affects me and she told me to send her what id like to be in the letter however I’m really struggling to think or if maybe my cfs issues should be in a seperare letter(for which I’d have to ask).

The current template is like this:

“He is under care of mental health because he has x mental health issues.

His mental health issues affect him severely such that he struggles with daily car activities eg eating, washing and so on.”

Now I need to add a line or two to discuss how cfs(a separate cobdition) affects my walking ability especially. Any idea what I might request to be added to the current template?

Maybe a third parapgraph ‘ he also has cfs which affects previously mentioned physical activities which affect his ability to walk aswell as the aforementioned activities’.

Does this sound ok or do I need to add more eg symptoms and explain what cfs is etc?
It seems a bit awkward just singling our walking but then typical activities affected by cfs are already mentioned for the mental health issue.

I could ask a separate Letter mentioning cfs diagnosis and symptoms instead of the mental health diagnoses and issues.

I’d be grateful if you could advise.

Thanks