What title would a man of the Victorian gentry (land owning classes) have?
There is a lot of misinformation here! First: the “gentry” as a class specifically excludes anyone with the title “Lord” – lords are nobility, not gentry! If your wealthy landowner is a member of the gentry (and he probably would be: the nobility in Britain have always been a very small class, unlike some Continental countries where everybody who is anybody has a noble title), he will probably just be “Mr Darcy”. (You would address letters to him as “John Darcy, Esq.” but he would not use the title “Esquire”, nor would anyone use it when speaking of or to him,) If he had ever done anything special he might have been made a knight, in which case he would be Sir John Darcy, and be addressed by everyone as “Sir John”. He might also be a baronet, which is a sort of hereditary knight, in which case he would still be Sir John Darcy.