Hi Vikki and Welcome to the forum, you might want to have a look at the following FAQ which explain where everything is
Welcome to Benefits and Work This is an FOI request that particularly relates to ATOS and ESA assessments. I am not aware of anything else in the public domain. However, I'm afraid that this has only ever been guidance, it does not hold any weight in law and, from what I have seen and experienced, is rarely followed.
www.whatdotheyknow.com/request/esa_assessment