Severe Disability allowance

I need advice. I was turned down for the severe disability premium in Dec 2015 (this benefit forn was sent automatically to me when I qualified for PIP). I was made aware during a phone call with the DWP this March that I qualify for this benefit as both my Son's had left home. I was also told I may have been entitled to this benefit (during the phone call) from Sept 2016 when my son went to Uni. I was advised to fill the form out, send it back, and it could be back dated. So, I have now been awarded this benefit, however I had to send in a letter of reconsideration regarding entitlement to back payments. I have done this stating that I wasnt aware that once my youngest son went to uni in Sept 2016 I would have qualified for this benefit. I received a call from the DWP stating that they have referred my reconsideration letter to their Chesterfield office as they can't make a decision as I should have advised them of a change of circumstance. I didn't realise that my son going to uni was a change of circumstance and that this was part of the criteria to entitle me the benefit. I informed the Council Tax people at the time he went to Uni and thought if there was any issues it would have been passed down the chain. I am waiting a response from the DWP Chesterfield office at the time of writing this. You've helped me in the past and your help and advice would be appreciated. Thankyou so much.

Hi Gordon, thankyou so much for your reply. I never had a response from the DWP in 2015 stating why. It was only a chance phone call this March that I was aware of this. As you said I will wait for a response from Chesterfield. How would I know what the criteria was!! I didn't think that my son going to uni would affect me in any way financially. Again thankyou for coming back to me I appreciate it. Thank you Welshy66