It has been theorized that Daemon Blackfyre set up a rebel capital in the Reach during his Rebellion. Considering that House Peake was one of Daemon’s primary supporters, isn’t it possible that this rebel capital was one of the Peake secondary castles, Dustonbury or Whitegrove? Dustonbury used to belong to House Manderly, indicating that it was on or near the Mander, possibly guarding a river crossing. And it would be one more reason for the Crown to seize those castles after the Rebellion.