VCS-County Court claim papers

Thank you all for answering.
I submitted the AoS few days back (within 14 days of date of service) on behalf of my mother.
She was issued the NTK as keeper.
On the day of the infraction she suffered a nasty fall and was not in the condition to walk. The car was collected by an another driver 90 mins late than the allowed 60mins. She is elderly and holds a blue badge.
The initial ANPR NTK was issued 7 weeks after the date of infraction. She didn’t receive it as she was out of the country and was also not received in the post.
She found out about the incident after the second NTK arrived, issued on 21 Dec but received in post after new year holidays. By the time she opened the letter it was too late to take any action as the 14 days period was up and no appeal was allowed. Few days later received first debt collector’s letter and LBCc in July.
Initially, she couldn’t figure where the location was to even send in an out of date mitigating circumstances appeal and according to all correspondence she had no choice but to pay up or face county court.
I now have to submit a defence with the above. I would really appreciate your advice.
Thanks again.

@nosferatu1001..Appreciate your reply.
1.Date of issue of CC claim: 17/08/18 (Ppc frequent this forum so was a bit afraid)
2.The Aos was sent in her name as defendant on 30/08/18
She's 75 and not computer literate. Im here to help her write up a defence.
3. The LBC was a demand of payment not allowing her any recourse to explain herself. Extenuating circumstances perhaps? Can she write up a separate letter explaining the entire situation apart from the defence.
4. She should be able to obtain a letter from her doctor apart from the other drivers witness statement.
5. I realise my tardiness dilutes the urgency of my asking for advice but it was a situation beyond my control and explaining myself would be just that hence, with due respect for reader's time I got to the point.
Than you again for taking out time and reading the post!