Hi JudyB
I can't tell you what to do here because you will have to make the choice yourself, but I would never advise people to include a letter that could damage their claim. Consultants don't write letters for the DWP and have no idea what they say could be damaging if taken out of context.
One option is to keep a diary for a week covering your breathing difficulties and include that. If you have a family member or friend who has witnessed your struggles get them to write a letter.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
