Although officially on vacation at Balmoral Castle, King Charles III’s work never truly ends, which has Queen Camilla frustrated as the monarch battles cancer. “Camilla would have been deeply unhappy that having only begun his holiday on Monday, he broke it off on Tuesday to do an incredibly intense engagement,” a friend of Her Majesty shared. “Of course, she understands it was very important and there is no way she would try to tell Charles what to do, but it seems to be extraordinary timing,” they added. “She wants him to slow down, she is afraid he is working too hard, and that’s before you…