Quick query on this one.
Does the Dragon Armour's "Immune to Flame, Breath, etc" attacks also work on a Monster if the character wearing it is riding one?

Or does "Mount" specifically refer to Cavalry models only?

For example, a Prince wearing Armour of Caledor (or just regular Dragon Armour) on a Star Dragon is in combat with, for example, a Lord of Change who is using the Master of Sorcery gift, has chosen the Lore of Fire and has cast Flaming Sword upon itself for some extra Close-Combat meatiness....I assume that the Prince himself is immune to the Lord of Change's attacks, but what about the Dragon?