This case may be of some use to you.
Look up London Tribunals register of appeals for case 2130491073
The key bit of my successful appeal was the adjudicator's words:
Second, and more importantly the vehicle is still moving out of the box junction when the CCTV footage stops. The Adjudicator must see the entire driving of the vehicle in and out of the box junction. I find this to be a serious omission.
Now admittedly my "offence" was "stopping, if it be that, [which] is hardly perceptible."
OP stops for a reasonable period. But nonetheless the CCTV does not show him moving out of the YBJ and adjudicator Teper says this is "a serious omission".