The twelve days of Christmas start on 25th December and they are a traditional time of feasting, and in some cases subversion of the established order. Christopher Hill does not touch on Christmas in his The World Turned Upside Down but Ronald Hutton in Stations of the Sun has carefully researched detail of the traditions of the period.
As Hobsbawm and Ranger underlined in their collection The Invention of Tradition, more or less all traditions are invented.
In that context it remains remarkably difficult to discover what traditions are associated with Christmas Eve. Since the arrival of the Christian Church in England and the rise of its influence over daily life, very roughly from the early Middle Ages, there has been some sort of Christmas Eve, evening tradition, of light- candles often- to welcome the appearance of Christmas Day. For the Church this signified the birth of Christ and for the peasant society England then was, it meant the end of a period of limited diet and the start of feasting.
Christmas Eve as Hutton briefly notes was not a time of drinking and eating but quite the reverse. It was the final day of a four week period over Advent where the diet was restricted and things like roast meats were not eaten. For the rich there were alternatives but for the poor less so. The 24th December marked the end of the diet and did so at its most austere. No eggs, cheese or meat were to be eaten on this day.
The Victorians and Charles Dickens in particular had other ideas about what the traditions of Christmas Eve should be