I too work shifts and after a 15 hour night shift a bowl of cereal just won't doo, but my Mum thinks eating in the street is common and we weren't allowed to do it as children, even now if I eat hot doughnuts fromm a van (my particular weakness even though I rarely eat sweet things) I feel guilty.
DS has, on occasion, pretended to greet my Mum causing me huge waves of guilt. DS is 25 and I don't know how he got to be so wicked!
Eating in the street - a guilty pleasure, but definitely chavvy.