Normally, CCTV is used to enforce restricted bus stops, and thus there is a video record of the alleged contravention. Yet here, Lincoln think it's perfectly OK to show an unoccupied bus stop photo as evidence ! I think I would be asking for much more information on the alleged contravention in any representations I submit. This would include full CEO notes of the allegation. There is a difference between stopping "in traffic" and this happening to be when the car was stationary partly in the bus bay area, and actually stopped at the side of the street, with traffic moving past the stationary car. This would be seen in a video.
As this is a postal PCN, there is only one opportunity to submit reps, then, if rejected, one can take them to adjudication. Certainly I would not pay-up straightaway, but submit representations on the basis that the contravention did not occur and the car never was stationary in the bus stop concerned.