I let him out of his cage and he spent all day investigating new places to hang out and demonstrating exactly what curtains mean to Budgies (obviously way better than that nasty ol' cuttlefish I keep giving him)
Then he finally flew to his cage instead of going up the stairs.
It took him another half hour to find the door mind you but at least it meant he had a good go on his iodine block (from outside) because he was so hungry. Eventually he worked out where the door is (on the other side) and went in.
Yay!
Perfect timing as well since i was going to start cooking and am going out for the evening.
I'll keep an eye on him for a few days now as he was nibbling various things like picture frames and the walls. He should be fine though.