As I understand it (do not take this as the gospel!!), teams will 100% be drawn into the group hosted in their nation (so England will always be in Group D), and will 100% be at home for all group matches unless the other team hosting that group also qualifies. So if Scotland qualify, they will play against England in the group stage, and that game will randomly be at either Hampden or Wembley. So you only miss out on it being England if Scotland qualify (~50%), the matchround they play each other is the one you have tickets for (33%), and it's drawn to play at Hampden (50%) - overall a ~8% chance England aren't involved in that game, ~92% that they are.