OP, has given me details which have enabled me to view their photos. They prefer not to make these, their details, public which is their choice but does hinder peer review.
Photos show car parked 3/4 on DYL with the remainder (rear) just inside a bay*.
IMO, the CEO was being generous in using the lower level penalty for 'not parked wholly...' when many would have gone for the more obvious 'parked in restricted street...' there being clear DYL under most of the car.
The traffic sign simply states 'Pay at Machine' and this is situated within the parking place. Unfortunately, the CEO's photo of the machine is not in focus and doesn't show charging hours, so it's not possible to know whether the car was parked during restricted hours. There appears to be an envelope on the windscreen, but not of the yellow and black variety.
OP, you need to make reps and reassess after you receive their response. As suggested by others, this in itself could drag victory from the jaws of defeat.
OP, as you've not made reps prior to now, you could do so based on the obvious if you were not the driver e.g. no indication as to whether the contravention occurred during the bays's operational time because this info is not carried by the traffic sign and the CEO's photo of the machine is out of focus and does not disclose the operational hours of the bay. If it occurred outside the restricted hours then the location should be considered an unrestricted length of street and therefore the contravention could not occur.
*- bay is not internally divided, so not being parked wholly etc. refers to the end of the parking place as opposed to an internal sub-division.
Wait for others.
