Kevin
Definitely include a note on the form for Capita to write to her contacts, but don't rely on them doing it.
Speak to the Consultants secretary if you can to see what information they are willing to provide, diagnosis information can be important but testimony about her problems completing each of the PIP activities is the thing that will help to score points.
If it will help there is a GP Notes document in the PIP areas that might help the consultant put some structure to anything that they might produce.
www.benefitsandwork.co.uk/help-for-claimants/pip Gordon