@Allergictoironing you are right about the likelihood of getting mobility. Back when it was DLA, I had to advise clients that if their non-mobility condition worsened, it might not be worth asking for a re-consideration, as, whether you wanted them to or not, they would always review mobility as well, and it was not unheard of for the mobility award to be revised downward 
I'm afraid I must add, that someone who is actually dying used to be able to get a fast-tracked DLA award. Probably the same with PIP? 6 months expected lifespan, but they will still continue to pay if you don't die. (I used to advise in a hospice as well.)
OTOH, if a limb has fallen off, they'll be back in touch sometime in the future to check whether it's regrown. OK, slight exaggeration, but not much of one 
Moorfields is a brilliant eye hospital, from all I've heard. I've got cateracts coming, at present my sight is unimpaired, but I don't drive at night unless I must, because of the increased glare.