November is too early in the season for all but the most pessimistic of football fans to worry about relegation but not for housebuilders. Not so long ago, Barratt, Taylor Wimpey and Persimmon featured in the blue-chip FTSE 100 but the industry’s big three have been demoted and joined Bellway, Berkeley, Bovis and Redrow in the FTSE 250. Relegation from …