I've just recruited the final two members of the Blades. Trouble is none of the three recruits seem to have changed to their Blade armor yet. Is this a bug or do I have to wait for a certain amount of time, or for something like the first dragon hunt before they change? If it is a bug how do I get them to change? Any console commands?

When I recruited my lot into the Blades they didnt get their armour until they went on a mission to kill a dragon. Try starting the quest, and fast travel to the location. You should find the Blades recruits with their armour etc.