From applying initially by phone and then returning the forms by the due date, to being awarded enhanced rate for both components, with no review for 10 years, took 2 weeks. No face to face interview. Decision was based on the information provided on the form and a letter from the Parkinsons nurse specialist. They didn't contact any other professionals, not even the consultant. Maybe having been diagnosed 17 years ago was enough to show that the situation will not improve but will deteriorate further for my OH. I did the telephone initial contact, as OH can't speak on the phone, and then filled in the forms, very slowly, with OH contributing to how his P affects his daily living and mobility.
It was very difficult filling in the form, and many tears were shed during the process of him accepting, and then putting in writing, all the things that he can no longer do, which had been denied for many years, BUT, if you are honest about how P limits your life, then I presume that you will be awarded PIP.