Jon--sorry for what you're going through. i don't have any help for your terrible problems with the bureaucracy as i am in the US and unfamiliar with NHS, except that i had benign tumor of the pancreas, insulinoma, and i was particpating for a while in a discussion/support group for that kind of tumor, and the group was started by someone in the UK and most of the members were in the UK.
Something i learned on that group about treatment through NHS that is not consistent with your experience, if i understand it, not sure that i do, was that if you had a tumor on the pancreas, even if it was likely to be benign, it was considered to be cancer until proven otherwise, and thus, such cases were prioritized and there was a rigid standard time frame (something like 30 days) at which point the case had to be treated. Any cancer diagnosis was treated as urgent, there seemed to be agreement on that, although sometimes cases could fall through the cracks and patients had to advocate for themselves, whether through their consultant or by changing medical centers. Again, this is foreign to me, just telling you what i read on that group where patients share experiences. i was on the group this year between June and September.
(Insulinomas are usually but not always benign and one doesn't know for sure until surgery and pathology of the tumor).
Reading your post, i was just wondering, when you say you were confirmed as having a tumor of the pancreas in October 2014, how was that confirmed? What diagnostic procedures did you have, and are the results documented, are there medical reports? Do you have copy of documentation or can you get it? Is there any more specific diagnosis than 'tumor of the pancreas?' Do you know what kind of pancreatic tumor you have? There are various kinds, with different treatments and prognosis. You said that in September 2014 that DWP staff stated that you have a 'terminal illness.' Do you know any more specific information about the diagnosis? I'm not sure what they mean by terminal. Did they tell you there is no treatment? or have they discussed treatment with you?
Sorry if my questions are ignorant. I don't know what a DS1500 is. i don't know what DWP stands for (i live in Los Angeles--here it stands for Department of Water and Power, not very popular).
I was just prompted by your post to write because i feel so concerned that you have a serious illness without much information about what it is or what to do in order to have treatment for it. On the insulinoma list there were people, including the person who started the group, who have malignant insulinoma and are living and functioning (working) after many years, although they had some really complicated difficult surgical treatmens for these tumors which, if malignant, can be recurrent.
Because i don't understand your situation, i can't help thinking that this might be a case for an attorney, if they are delaying treatment for a 'terminal illness,' which could make a difference in your outcome.