I applied for PIP back when it first came in with mental health problems. I know this isn't relevent to you OP as your problems are with incontinence, but my story might help you a bit. I had to have a home assessment as the only place they could offer me an assessment was in a town 20 miles away. I explained that I am agoraphobic and could not get there. I had to fight for months just for a home assessment. The assessment focused mainly on physical things, it isn't really applicable to mental health at all. When I recieved the copy of the assessment the assessor had just put what she wanted down. There was a lot I said that wasn't included.
I appealed their decision, unfortunately the DWP also turned me down with the mandatory reconsideration they have to do. I took it to appeal. Luckily there is a voluntary agency in my area which helps with benefits appeals, so I was able to speak with one of their solicitors for a hour which really helped me as they felt I should have been entitled to it.
I finally got my day in the appeal court. The tribunal people were lovely, which was good as I was a wreck (just leaving the house was very difficult for me, going into a room with unknown people to discuss all my faults was nearly unbearable). I was in there for about 10 mins and they gently questioned me. They sent me out whilst they made their decision, which took about 30 seconds! They awarded me the higher rate mobility for 3 years (one year post dated). However all this took 14 months and seriously affected my already fragile mental health.
So what I want to say to all of you who are having to jump through all these hoops, is persevere. It is hard, it is soul destroying, and ATOS are c**nts. But you do not have to accept their decisions. You can ask the DWP to overturn it if you feel it is wrong, and if they don't you have the right to an appeal with people that don't have their own agenda and will accept evidence of your disability/ies that ATOS will not. Also make sure you have as much evidence as you can get to support what you are saying. Despite ATOS asking for all my hospital and dr's details, they will not check anything themselves, if you do not provide evidence all they use is their assessment.