Please ring TfL and get them to send you the video. It will come as a DVD. They then freeze enforcement for 2 weeks to allow the video to be produced, posted and received. You must be careful, though, and if the DVD hasn't arrived in about 10 days, contact them again, because the unfreezing occurs automatically, and you don't want to miss the deadline for subitting reps.
My view is that you have a good case, in that you stopped in the bay, read the sign, saw that it was for EVs, so drove off. This scenario has won appeals at London Tribunals.