As the video (which is their primary evidence) shows, you were stationary on a red route at the time of the alleged contravention.
The burden falls to you to establish a legitimate reason. IMO, 'circumstances beyond your control..' is all that's available, but you weren't broken down etc, therefore you would need to show that you were unable to move forward. Clearly, if you were in a line of stationary vehicles in the traffic lane then this could be argued(it's what the exemption addresses).
But IMO you weren't because the traffic was moving past and beyond you.
As regards the contravention, I cannot see a probable defence.
As regards enforcement propriety, the NOR does not comply with the regulations in that:
The statutory period which must elapse before the authority may serve a charge certificate and which must be given in the NOR has been misstated;
Similarly, the statutory 28-day period during which you may make an appeal has been misstated,
In both cases it's 28 days beginning on the date of service;
Furthermore, the NOR omits reference to the adjudicator's power to register an appeal after the expiry of the 28-day period.
A procedural impropriety means a failure by an enforcement authority to observe any requirement imposed on it by[in this case]:
(a)
(b)
(c)these [the 2022 Appeals] Regulations.
'Procedural impropriety' is grounds for appeal.
Wait for others.
Pl post 'the enclosed form' referred to in the NOR. I doubt that this gives the correct info and in any event even if it did you would have 2 sets of contradictory instructions. I also doubt that the form would be included in the authority's evidence at a hearing and therefore the NOR would stand on its own.