Here's the best I can come up with in the circumstances:
Dear London Borough of Haringey,
On the day in question I was visiting my parents and I was well aware of the requirement to display a valid visitor's permit between the hours of 10 and noon.
I realized at around 9-9:15 that I needed to scratch out a permit and go outside to display it in the car. This was around Breakfast time for my two children. My wife was still upstairs so I had them both to feed, I put the one year old in the highchair and gave her Weetabix. The 2 year old was seemingly occupied with his cereal so I thought I'd grab a moment to scratch out the permit. I gave my phone a cursory glance to check the date while keeping an eye out to prevent a Weetabix tornado. I saw it was the 1st and proceeded to scratch it out.
Calm moments don't last too long and soon noticed the 2 year old run out of his seat, I carried on scratching slightly distracted and must've scratched April by rote. It all went downhill from there... I heard a muffled thud from the dining room and my oldest bursting into loud wails. I grabbed the permit and ran. By the time I had the situ under control I really needed to run to the car. however I came back to the kitchen and discovered that the 1 year old had happily used my absence to practise her make-up artistry - with Weetabix! I must admit by that point I was a bit flustered and yelled to my wife to come down while I ran out to the car. I finished scratching it out and made a dash for it. When came back I had the honors of weeding the Weetabix out of said youngest's hair, and I didn't give another moment's thought to the permit. It wasn't until around 11:45 when my mother mentioned some event that was due to take place on 9th May and she said "next week" that it hit me. I zipped out to the car but it was too late and a penalty charge notice had been issued.
I would point out that 1st April was not a Wednesday, while 1st May was a Wednesday. The last 1st April that fell on a Wednesday was in 2020 and the next 1st April falling on a Wednesday is in 2026, but as the permit requires the year to be scratched out there is no possibility of this permit having been used in 2020 or being re-used in 2026, this does not render the permit compliant but is clear evidence for the fact that there was no attempt to deliberately abuse the parking facilities nor has there been any attempt to re-use a permit.
In light of these mitigating circumstances I would invite you to consider not pursuing enforcement on this occasion, and you will no doubt be aware that the fact that a contravention occurred is not, in and of itself, a reason to refuse to exercise your discretion as requested.
Yours faithfully,
Send the representation online and keep a screenshot of the confirmation page.