They are either incompetent or crafty, because the video, which is the sole evidence, is not available, even though frames from it are shown. It is impossible to judge from the photos whether an offence occurred, although it would seem your father drove into the box a short distance behind a bus which is always bad idea in London.
If your father can give more information on the incident, it would help, but it's difficult to help without seeing the video. If the matter is taken to London Tribunals, WF would have to produce the video for the adjudicator to view.