IMO, your circumstances go to mitigation only which an adjudicator could not consider.
If you drive, then you're deemed competent to understand and comply with traffic signs.
IMO, if you were to take this further then as a minimum you would need to obtain written support from competent persons/bodies regarding your claim as regards your son's issue with alighting when you aren't present.
As regards the signs, does anyone know what the actual prohibition is in this street? The council's position is that this is as per the sign and is 'actively enforced during term time'.
IMO, this is unlawful.
If the order states 52 weeks per year then officers are required by law to enforce such a restriction. It does NOT lie with officers or members to interfere with the law.
So, is it a 'term-time' only restriction in law i.e. in an order, or not?
OP, and judging by the addressee on the NOR, there's a backstory here. Who is 'the Company Secretary'?
Are you, as in you by name, actually the registered keeper. If so, then 'The Company Secretary', which indicates a corporate body and not private individual, cannot be you IMO, although you may be authorised. Pl clarify who's who so that should this go to appeal this is conducted by a competent person.
I must say that the odd numbers in St Andrews Road have more than their fair share of entries in the Companies House registers!