That's a very good point @BemusingBrandy, I hadn't spotted that.
When Salray was writing TSP, by this point the 2015 consultation had taken place, Moth had been waiting for this consultation, a referral had been made, apparently one referral had gone astray. This was an appointment to try to find out what was causing Tim's unexplained symptoms, it was not a routine appointment, it was a long awaited specialist appointment.
So after this consultation the idea to retrofit the diagnosis must have taken place, was it Sally's idea or Tim's, we don't know. We don't know if Salray had started to write TSP in a similar vein to the raffle book, and saw this opportunity to add an emotional hook that would transform the whole project. She had Simon's book for inspiration, and it was very clever to place themselves walking ahead of Simon, it gave credibility to the timeline and with being ahead of Simon, phychologically it doesn't feel like she could be copying him, even though her book is written after his has been published.
I have thought long and hard as to why Salray had to have it all, homelessness and terminal illness, she might have wanted to move the house repossession and place everything in 2015, but knew that this could be easily checked by anyone with the knowledge and desire to find out. Tim's health is protected information, she probably didn't think she would ever have to prove it and patient confidentiality would protect the lies.
Even now, the letters are there for everyone to see, the evidence of deception is there, but most people are still not seeing it. Just looking at the first letter 2015, Tim has either withheld the fact that he walked the SWCP, rather important information for a man who is complaining about an impairment of his walking, or it never happened. Yet that was missed by us for months, also his plan for a future walk, both spotted by @SimoArmo.
The diagnosis given was tentative and certainly not as Salray has portrayed it. As for the book review, whether or not Dr Davies is Tim's diagnosing consultant, he is a neurologist at the Walton unit, CBD/CBS is a rare condition and a book with it as a central theme would be of interest. I do believe Dr Davies wrote the review himself, I believe him to be a very intelligent but unworldly man, I also think the Walkers have played him, Tim and Sally have manipulated people all their lives.
The fact that they haven't given the consultant any information about walking at the 2015 consultation, proves to me that they did not walk the SWCP, they went on some walks. In this first consultation, Tim is giving the impression that walking is a problem for him, unexplained and mysterious, along with other symptoms in the left of his body. The consultant is seeing Tim with the knowledge that Tim has been having these symptoms, that so far do not seem to have a physical cause, for instance injury (falling through barn roof not mentioned).
As far as this consultant is concerned Tim has these unexplained symptoms, his colleagues at the pain clinic have not found a cause, so the neurologist is looking for signs of a neurological cause. The only thing he finds that has significance to him are the datscan results and the examination of Tim's eyes, he makes a tentative diagnosis. But as @ThisQuirkyRaven pointed out in an earlier post, both of these results can have other causes.
I think the reason Salray wrote about the consultation in the way that she did, in TSP all the, no you are wrong, she was trying to future proof, when Tim didn't turn out to be dying, she could say that she never believed the diagnosis, she was reluctant to accept that Tim had CBD, it was the consultants fault, the reality of the 2015 consultation is very different. Once a patient has reached a neurologist, the neurologist will be looking for some evidence of neurological issues, if the consultant had been of a different specialism these test results could have been interpreted differently.