Have (possible) extra info, after posting... any experience?

PIP isn’t about your ability to work. 

SonOfYorick said:

should would it be worth pointing it out in context of stopping me having any general access to driving , never mind work ?

Thats the point of PIP, how your disability affects you, and you alone, So the answer is yes. But it is also important if your disability prevents you from working, because it affects your ability to achieve self actualisation, and as a consequence be separated from social life, having goals in life, being motivated, having stable and meaningful relationships etc

So tell them all, driving, work etc, everything affected from your disability.

With all that said, if not already, explore Universal Credit and LCWRA.

SonOfYorick said:

It’s at the point now where I’m writing my letter requesting a tribunal. 

Is the driving and work stuff worth mentioning at this late stage ?

Having spoken to two very experienced veterans of DWP stuff, on the decision of 
do I go for one short see you in court , or a lengthy request plus complaint, 

Ive gone for the 3 pages of surgical takedown and reiteration, but I’ve stuck specifically to things I’ve already mentioned , which doesn’t include driving  

That will depend on what information you have already given. Less is often more, especially with medical evidence. Sending multiple pieces of evidence all saying the same thing isn’t helpful.