Her Majesty, or more precisely her deputy correspondence coordinator, replied very promptly and courteously to my letter (see my post of 30 August).
The key phrase: 'as a constitutional Monarch, The Queen acts on the advice of her Ministers.' It is not the Queen's fault, but what it means is that Her Majesty has to do whatever the prime minister tells her.
This was fine during the era of 'decent chap' politics, when the British constitution was not much more than an assumption that no political party would foist on the British people any prime minister who was not a good sort, and that anyone who reached these exalted heights could be trusted not to behave undemocratically.
Sadly in the era of Boris Johnson and a Tory Party that has gone mad, this is all hopelessly outdated, so it is worth writing to the Queen on this subject. There is just the chance that if she gets enough letters, the palace may be more resistant should Johnson appear with an even more unreasonable demand.