Getting medical evidence

Hi, more and more often I read about the difficulties people are having obtaining medical evidence to support a benefit claim. I have experienced this problem too with my DLA to PIP application (I have lost out there, but another story. I submitted three expert evidence reports which were not helpful at all. The fact is GPs have been advised by the BMA and the DWP? that it is not necessary to waste time writing letters of support, that the DWP will contact them if needed. I have heard the DWP rarely do this. I have tried very hard to persuade my GP to do this, but she argued that she could only explain my condition but not how I cope on a daily basis, which is what is required. The same is true of a consultants report, how can he say how someone copes with daily life without witnessing it which is what is required. So most reports are useless in this scenario? My psychiatrist said that I would have problems with daily life, and needed help and support to take medication to cope with Bi-polar, another report from an occupational therapist, explaining problems with mobility due to ME and severe osteoarthritis. The mental health problems were completely ignored and I was told I didn't have a mental health problems, despite being under supervision of the affective disorder team, and visited every month for six years or so. I put together a letter for a mandatory reconsideration, and had to ask my psychiatrist again for another letter, which bless him he has. But I doubt if it will help. Then comes the Appeal, if I can face it. Do I have to ask yet again? Have consultants not got enough to do but write yet a third letter of support? It worries me. GPs are not providing letters, consultant letters are not enough unless they address the descriptors, but who can tell them them how to write their evidence? It looks to me that I may go to Appeal without new evidence as I have now four previous letters, but nothing from GP. Where do I go next for help? It seems to me that the DWP want to make medical evidence not so important, but to depend on the Assessment findings on the day only. Is it worth going to Appeal with no extra evidence, and I can't get more? I know this is my second message but I do feel the problem of medical evidence is prominent in most people's minds when applying for benefits.