Heroes and Boys
This little snippet I found in "The Cambridge Guide to Women's Writing in English" by Lorna Sage: Heyer herself describes her heroes as "Model No. 1" and "Model No. 2". I don't know which is which, but one is "The Avon Type" and the other is "The Sherry". The former is the often older, always urbane and frequently cynical hero as exemplified by Justin Alastair, the Duke of Avon in "These Old Shades". Others of this type include his son Dominic, the "Devil's Cub", although he is very young - possibly the youngest Heyer hero; Mr Beaumaris in "Arabella" and although he is not the hero, the "Black Moth".
The latter type reaches the pinnacle of its success (IMHO) in "Friday's Child" in Sherry. Others of this type include Ludovic Lavenham in "The Talisman Ring", and Jack in "Black Moth". These men are the younger heroes, enthusiastic and a little boyish. They almost never keep mistresses or commit any really bad sins. They are frequently paired with an "Avon" type hero as a double-romance novel, as is the case most notably in "The Talisman Ring".
Regular readers of Georgette Heyer's work have no doubt worked all this out for themselves, but it is nice to know that she did it deliberately.