Hedgehogs have very strong sense of smell so he may well have smelt the food you put out. Also I think they sometimes get used to the sound of the bowls being put down.
Sounds like he is getting a bit too used to the cushy life of having his food right outside, so he doesn’t need to do too much!
I would take the advice of Tiggywinkles as you suggested re. the scratching. It may be that if he keeps going back in the box, that he is getting continually reinfested with whatever it is. Really nice though, that someone has taken to your hog house.