I have been involved in benefits advice for 25 years.
Many people make the mistake of getting the forms and filling them in just using the supplied guidance notes.
They also make the mistake of thinking the assessor is on their side, they are not, or that they are qualified to assess them, they are often not.
The DWP regularly employs as assessors people such as physiotherapists or GP nurses or trainees.
Fine medical professionals I am sure but qualified to assess a claimant with Asperger or MS or the after affects of brain surgery?
I think not.
This website offers a wealth of information on applying for benefits.
https://www.benefitsandwork.co.uk/
A small annual subscription gets access to direct advice for claimants on how to fill in application forms for a variety of benefits. There is a section devoted to PIP applications.
It shows how to fill in each question to maximise your chances of acceptance. It shows what to avoid in answers.
It also gives advice for strategies to follow at the interview.
There should be a large sign explaining your rights to record the interview. I have never seen one. Any audio recording has to be done in duplicate there and then and a copy given to the assessor.
Bugger that for a game of soldiers.
Write everything down.
I always attend with claimants as their advisor, as is their right.
I note the start time and finish time.
I take a note book and transcribe as much of the interview as possible.
This can be invaluable as there are many recorded cases of assessors conclusions being completely at odds with the presented evidence. Examples are given in the website.
As for evidence to send beforehand make sure it is from as highly qualified a source as possible.
If you are turned down the website offers full guidance in the appeal procedure.
If you get to appeal judges look very poorly on lowly qualified assessors overturning the written evidence of a specialist neuro or orthopaedic surgeon.
Last year they rebuked the DWP for what they considered to be malicious, unqualified rejections to the extent they threatened to start fining them if they continued with their policy.
Please pass this on to anyone you know involved in applying for a variety of benefits.
I again recommend the documentation via subscription.
Here it is again
https://www.benefitsandwork.co.uk/
If nothing else people should sign up to the fortnightly email newsletter that exposes every snidey underhand trick carried out by the DWP and the snakes who have been running that department for years.
It also keeps you updated with every change the DWP bring in to try to disqualify more people. And believe me, they do.