The larger Brood chamber is not well suited to British Native bees, but it is used in the southern parts of England, where the majority of stocks are of foreign and mongrelised strains that need the extra warmth and generate large amounts of brood.
Whilst the 22 mm width top bars are included in the drawings for the other B.S. frame types. They are more trouble than the small savings in cost are worth in the increased handling time, that they incur due to the excessive brace comb that is built on them. They are not included here as it would be silly to suggest that such a hindrance would be tolerated in a 'Commercial' undertaking. But I wish to mention that they do exist and will be found among secondhand equipment.
This type of hive has its supporters, but it is not successfully used much further North than a line that runs East - West through Northampton.