Lisa,
I know how maddening the DWP's inconsistencies can be, but at the end of the day the crucial thing is to get a fair decision... And it looks like you are going to have to go to tribunal for it on this occasion.
It's tempting to lay out in gory detail just how badly DWP have handled things, but you need to ask yourself to what extent it strengthens your case to be awarded ESA.
Sounds to me like you have loads of evidence to prove you should receive ESA, so the MAIN focus needs to be on presenting that clearly at tribunal.
Good luck!
Andy.