Claiming refund of car tax back payment?

I have been awarded the higher rate pip for mobility and after about 6 months I have realized that I could of been claiming free car tax. Can I claim the amounts already paid following my award date on my decision letter from the DWP?

You won't be able to claim a back-dated refund on your car tax. It's an exemption you have to apply for and is only valid from the time you apply. I have a relative who has worked for DVLA for many years and this often comes up.

i applied for my half price tax on my current car and i was sent a cheque back for half the amunt as requested and also given another form to put in any other car registrations i have had whilst i have been on pip, these went back 2 years and i was still given a refund on all the past times i didnt know i was eligible.