Looks much like some mixed type of Old English Game birds. The rooster's tail looks true to breed, but I'm not familiar with this breed's colors. They have many. The odd thing is that the wattles, comb and earlobes are run together. That's not normal for the breed, but Old English Game is my best guess. They did originate in Britain, you are in England, so it's a match! Maybe someone else with experience with Game breeds will help more. Absolutely beautiful chickens!