How in god's name do posters know he had radiotherapy on Monday?
They don’t (obviously) but what they do know:
5 February (i.e. Monday)
Buckingham Palace announces that King Charles has been diagnosed with a form of cancer discovered during his recent treatment. The type of cancer has not been revealed, but according to a palace statement the King has started "regular treatments".
I'm not an oncologist, but I, and many others know from personal experience of relatives with cancer that the three main treatments for cancer are surgery, radiation and chemotherapy. Charles obviously hasn’t had surgery. So it is very likely indeed that he’s had radiation or chemotherapy if treatment has already started.
Charles was in Sandringham on Sunday (photographed going to church there), returned to London at some stage after that, and went back to Sandringham Tuesday afternoon.
So, again, it’s most likely that he came back to London to start his treatment. Given that the Palace announcement on Monday evening said it had already happened, it was most likely on Monday.It might have been Sunday of course, but Monday is obviously far more likely for scheduled treatment.
So there you go - no knowledge, but a high likelihood.