Hi Bunter can only tell you what happened to us and hope this helps.
My wife has been in a wheelchair for a number of years and when our UK badge expired we went to the Social Services and was told to go to our GP to get Spanish medical evidence. The doctor gave us a letter straight away, which we then took to the S.S who made us an appointment at Jesus Hospital which took a couple of months, upon the doctor seeing my wife she sent a form back to our local S.S who gave us the Blue Badge a few weeks later. My wife's hospital doctors were also willing to write the medical evidence if we required it.

At the hospital I normally block the road near to the ramp take the wife up into the hospital, ignoring any horns then come back and go and park the car, as she refuses to sit outside with a sign I have written stating a husband, several dogs and cats to feed please give generously.
Yours a Hospital veteran visitor Bulldog.