Why every King George V-class battleship needed command space

Did the royally named King George V-class ships have more admiral facilities than Anson and Howe?

Not because of their names; capital ships generally carried some flagship facilities because any of them might need to host an admiral.

A royal ship name did not automatically bring more admiral's accommodation than an admiral name. By the late 1930s, however, every new capital ship was rare enough that it might need to serve as a flagship. Designers therefore had reason to include at least some command facilities throughout the class. The exchange separates ceremonial naming from the operational requirement to shift an admiral and staff between available battleships.