Retrospective backdated disabled council tax?

Sorry if this topic is not allowed ..I have been eligible for disabled council tax for internal
work carried out by a local authority grant .
my situation is that the work was completed in 2008 after my return home from major surgery & rehab. I had never heard tell of the discount.
I just can’t read and absorb any information let alone the information on the back of my council tax form due to high doses of controlled drugs.
realistically is there any chance or legal precedent that I may get any of it it backdated? Thank you .

Thank you any advice is greatly appreciated.