Manual of medical conditions

I have read in another post (which, annoyingly, I can't seem to find now) that there is a manual of medical conditions - not sure if this is used by assessors or DWP DMs or both - that shows the likely difficulties which may arise from those conditions. Does anyone know whether this is publicly available please? I have been awarded PIP DL and Mobility, both standard, but not for the condition which causes me the most trouble. I want to check whether it's in the manual (I suspect not). I've recently submitted an appeal in respect of activities 8, 9, 10 and 11 and whilst I've put in a neuro-psychology report evidencing impairment in some cognitive domains and evidence (from research) as to how these impaired domains affect daily life and given details as to how it affects me I've been refused any points on these activities. I understand from a telephone conversation with a DM at the DWP who consulted with the DM who reviewed my case at MR that it is because I am able to drive (I drive alone only on short journeys with which I am very familiar and have been very familiar for many years before the onset of my cognitive difficulties). The assessor found that as I'm not receiving any medication or support for my cognitive difficulties then there isn't any evidence of cognitive impairment (clearly she seems to know more than the neuro-psychologist and the battery of performance validity measured, nationally and internationally recognised "gold standard" tests used to produce the neuro-psychology clinic report). I put in evidence from the head of psychology at my local health board at MR commenting that they are not resourced to run a cancer related cognitive impairment programme although they might if they were resourced and I've argued that the absence of therapeutic support is not, therefore, evidence of no condition. Anyway, I think my starting point is the manual to see if CRCI is even recognised within it and to find out when it's likely to get updated as the weight of evidence of the existence of and therapy for CRCI is enormous. Thank you in anticipation of any help in identifying and maybe even pointing me in the direction of where I might find this manual.