These solutions will give a general outline to understanding the puzzles, but won’t necessarily go into full detail, to preserve some of the secrets of the hunt for The Treasure (which incidentally will be available to claim from next week…).
First, it’s important to work out where you are. The clues of the riverbank and the observatory show that you’re near the Greenwich Royal Observatory in London, UK.
Over the course of the story, the observatory ball is seen to drop. This means it’s just before 1pm. Looking at the scroll, and noting the fact that the rabbit follows one of the instructions during the story, we can see that’s it’s specifically 1st September 2021 (the same day as the puzzle was published).
This is important for later.
The first thing to do with the list of instructions is put them into chronological order. The first instruction tells you the string that’s going to be modified throughout the course of the puzzle: FINDALICE.
Following the instructions in order, and being careful to keep track of the Queen’s adjustments to the alphabet, results in the string ITSNOGOOD or it’s no good.
But in the story, the rabbit, after completing the 12:59pm instruction, says: "Oh. It’s no good, it’s no good! That can’t be right…” So something has gone wrong.
A hidden extra instruction in mirror writing at the bottom of the queen’s note must be applied after 500 years have passed.
Since the first instruction was on September 1st 1521, and it’s now September 1st 2021, this instruction should apply just after the rabbit vanished. But applying it results in gibberish.
Going over the list more carefully, it should become apparent that several of the dates do not exist in any year. For example March 32nd, April 31st and February 30th
Looking even more carefully, and bearing in mind that we’re specifically in the UK, the list of fake times gets even longer:
Leap Years February 29th generally only exists in years which are divisible by 4 and NOT 100, unless the year is divisible by 400. One exception occurred in England in 1700, which WAS a leap year in the Julian calendar.
Gregorian Switch Speaking of which, in 1752 England changed from the Julian to Gregorian calendars, which meant September 2nd was followed by September 14th.
Daylight Savings Daylight savings varies around the world, but we know we’re in England from the story clues. In England, April 17th 1932 2:30 am didn’t exist, because the time jumped from 2:00 am to 3:00am.
All this information is freely available on sites such as https://www.timeanddate.com/
Finally, there is one more daylight savings trick: October 29th 1972, 2:30 am.
Not only does this time exist, it happens twice: daylight savings means you repeat the hour from 2am to 3am. When the clocks reach 3am the first time, they revert back to 2am.
Processing only the instructions for times that exist (including double running the October 1972 instruction) then running the final hidden command, gives FUNDANODE or fund a node.