Is Decision-Maker's Assessment different to ESA85?

I am in ESA WRAG. My last WCA face-to-face medical was June 2014. The doctor suggested a 'prognosis' of 18 months (ie, ending December 2015). Yet my entitlement has just continued without further communication ... until I received a blank ESA50 two weeks ago.

Now I am simultaneously preparing myself both for sanction by my work programme provider and for a negative re-assessment of my ESA entitlement, and to aid my defense I want to learn what the DWP already absolutely acknowledges to be my condition and symptoms.
I have the ESA85 Medical Report Form from June 2014. There are remarks (not points) against three of the descriptors. But:

a) is there a document I can request which represents the decision-maker's own assessment in June 2014 (after receiving and maturely comparing both my ESA50 & the doctor's face-to-face ESA85)?

b) presumably, since December 2015, my claim has been reassessed by a decision-maker alone (without a new ESA50 or ESA85). Is there a document I can request which represents this assessment?

(I'm sorry, like all newbies I am asking lots of questions)

Thank you again Gordon, already that £20 membership seems well worth it.
LT54 - excellent thank you, I am all prepared now for my phonecall to them.

Re: Do I actually know whether a reassessment was done without my input?

No. But surely the alternative is that nobody at the DWP has bothered to look at my entitlement since June 2014 ... nigh on 3 years!