My comments were intended as constructive criticism.
I won't be using the form personally as a) it would be too complicated for me and take me too long to amend it, b) especially as I won't be able to see my GP and discuss the form with him before he completes it, I can't risk him misunderstanding and ticking the wrong thing, so that I have to ask him to re-do it, which would be bound to irritate him and I probably wouldn't have time to do that anyway.
One last suggestion. When I did my ESA I gave my GP a series of questions suggested by Rethink, designed to make his answers address the relevant considerations. Taking this concept for PIP and the Moving Around category, the question could be something like "Bearing in mind the requirement that I can do so "reliably" (the meaning of which is explained on p.1), how is my ability to stand and move around outdoors affected by my medical conditions or medications? Please specify if I'm unable to stand or move more than 1 metre, either aided or unaided, or roughly how many metres I can move without experiencing severe discomfort (e.g. breathlessness, pain, fatigue) or being incapacitated by the effort for several hours or more afterwards."