Backdating of UC carer element

My client has had regular and substantial caring responsibilities for looking after her disabled brother for some time and for a while has claimed CA, with the UC carer element being applied for this period without issue. However, they refuse to go back any further asserting that she did not report her change in circumstances when it occurred and there are no ‘special reasons’ as to why the request for supersession should be admitted late. Reg 36 of The Universal Credit, Personal Independence Payment, Jobseeker’s Allowance and Employment and Support Allowance (Decisions and Appeals) Regulations 2013 specifies that the Secretary of State must be satisfied that…“due to special circumstances, it was not practicable for the applicant to give notice of the change of circumstances within the relevant notification period”. However, I cannot find any UC guidance or case law on the matter of what constitutes a ‘special circumstance’ in this instance.

I am just wondering if anyone has tested this point at tribunal and how ‘special’ the circumstances need to be. If someone had covid/ill health in the AP in question would that be considered as special enough? or a relationship breakdown? or home schooling your children? Presumably, if someone has been caring for some time, they could choose to ask for the supersession to take effect from the AP in which one these ‘special circumstances’ applied to stand a greater chance of success?

Andy