Here is a link to an interesting paper about a certain Roger Machado, who is known to have been Henry VII’s herald. It seems that before then he’d been Leicester Herald to Edward IV, Edward V and Richard III, but deserted Richard late in 1483 to go over to the Dark Side. Er, sorry, to Henry Tudor.
I don’t know how these things were done in the 15th century, or who appointed heralds, but if this one actually was Leicester Herald to Edward V, surely this is a pointer to Richard’s having fully expected to see his nephew on the throne? This, to me, is evidence that the accusations of More, Shakespeare & Company were untrue. The Duke of Gloucester didn’t have an eye on the throne from the outset. So his preparations for Edward V’s coronation were honest.