[edit: I am viewing the forum from abroad and have noticed that sometimes images are not loading, therefore if you have posted these please see my comments in this context]
Your posts are confusing.
On 24 April you posted: 'I’m going to Canada for 5 months in two weeks time.'
Where are you now?
You also posted that you had actually received only one PCN and speculated that as you had driven in the zone regularly more would follow. But in all your subsequent posts you've not referred to receiving any. You also refer to using a family member's address for DVLA purposes which IMO flags up another issue.
Also you posted in your draft: Because of the slowness of the system and the time it takes to process and post PCNs, I did not receive the very first notice until approximately a month after my first entry into the zone.
As you're hoping for their discretion, I would tone down this point. Also, it is very, very unusual for what you claim to be the case unless the vehicle concerned was hired or leased. But this would be unlikely for a car of your age. The applicable date for service is 2 working days after posting, not when it's forwarded by a family member.
We haven't seen any PCNs or timelines, which we would normally check for procedural compliance. As far as I can see, you told us the latest date for reps for PCN 1, let's hope your calcs are correct.