I've published the first chapter of a sequel to this called Brothers, Sisters, Sons and Daughters, here's an excerpt below:

The Queen paused then continued in a lighter tone:

"You were Master of Coin before the position was given to my little brother. Prior to his departure from the capital, he frequently bemoaned the poor state of the royal finances."

"Wars are expensive, your Grace, the treasury was always replete under my watch."

"My brother seemed to disagree, he was rather fixated on the idea that you had been guilty of some kind of mismanagement. I have no doubt it was his way of covering for his own failings, but as I'm sure you appreciate, now he has the backing of Highgarden, it is not so easy to keep him in his place."

Littlefinger could have guessed at her rage about Tyrion's change in circumstances. He had rather been hoping that this was the purpose of their meeting.

"I thank you for the warning, your Grace, but there is little I can do if your brother seeks to slander me to cover his own inadequacies. I can hardly wage a war on the Reach!"

"You do not need to wage a war to rid yourself of one man, my lord."