With respect, I disagree and I'll set out my thinking.
There is no ISA (wheelchair) symbol on the sign, therefore it is not a 'parking place reserved for disabled badge holders.'
Instead, there is the standard 'P' and it is a 'Parking place' - see item 2 of the Part 4 Sign Table -
https://www.legislation.gov.uk/uksi/2016/362/schedule/4/made(the bay also looks like it doesn't meet the min. size requirements for a disabled bay)
IMO, it is a permit bay and the type of user and permit identifier are Disabled Resident Permit Holder E.
The other way of looking at the issue would be that if it was a dedicated disabled bay then as it doesn't carry the ISA symbol (column 3) then this wins on its own and it's not necessary to explore column 4 issues.
OP, the car was parked without displaying or holding the required permit. If you are going to rely upon an exemption, in this case loading, then it is your legal burden to prove your entitlement.
The CEO's photo shows an unattended vehicle.
You claim that you were in the process of '..loading at premises adjacent to the parking place in which the vehicle is waiting and the vehicle does not wait for such purpose for more than twenty minutes or for such longer period as a parking attendant may approve.'
So, IMO you need something like:
On ** I had been visiting ** who lives at no. *** which is a property adjacent to the parking place in question....and then your account. I suggest you start with this because as regards the facts regarding what you were doing, you're the only one who knows and there are very important matters which as yet haven't been aired. Your reps leap straight into legal matters when, if you are entitled to the exemption, the only issue is to set out why you are entitled.
For example:
Looking at your photo, there's enough luggage etc. for an army. If it's yours, then you must have been stating..in which case if you only moved your car into the parking place at the time of loading, where was it until then and why couldn't loading have waited until another parking place was free etc. etc.
'Adjacent', which I think is key, is not defined and therefore subjective. Here's one I saw online:
Adjacent means close to or near something. You may consider the people up and down your street to be neighbors, but your next-door neighbor is the person who lives in the house or apartment adjacent to yours. Adjacent can refer to two things that touch each other or have the same wall or border.