Your honesty does you credit but will see you losing.
In effect you are saying you followed the bus into the box and stopped because it did.
That is the contravention cited and fully made out.
The evidence is what will be used to prove or disprove the contravention so work on what can be seen, not what you know.
The video shows you entering the box behind the bus but seeming to be steering for the left hand lane.
The video shows you braking as you were steering.
It also shows a moving moped sneaking up the inside while you were braking.
So maybe should be phrased as was stopping due to the moped to be exact.
TBH I regard it as the stutter dance polite people do when trying to pass each other in a doorway.
Step left, step right, stop, after you, no after you.
At the end of the day, it is either grab the discount or be ready to take this to adjudication where an adjudicator will look at the video, listen to what you have to say and decide.
IMO, challenge now with the best light you can put on the evidence and that will be on the table at adjudication.
The less you try to justify each little movement, the less there is for anyone to pick holes in.
