especially enjoyed the detailed description of London at the time. Thanks for the work devoted to its compilation!

Attempts at solving the quizz:
Ch. 19 The builder of this edifice also improved Britain's mail coach system.
truly amiable John Palmer Esq. ... building Theatre Royal, ...(the late amiable and intelligent gentleman who invented and successfully carried into execution the popular plan for the improvement of the posts of this kingdom by mail coaches etc), who rebuilt and considerably enlarged the house and, having connected the Bristol theatre with it,

Ch. 20 Where does a Gainsborough portrait of Captain Wade reside?

Octogon (room)of 48 feet diameter, adorned with a portrait of Captain Wade by Gainsborough

Ch. 21 Where can one keep "the commons" and "the term?"
My downfall - is it perchance to do with The Temple in London or Tunbridge Wells??

Ch. 22 All persons who are decently dressed may enter here.
All persons who are decently dressed, without any regard to fashion, may freely perambulate the pump-room.

Ch. 23 Where are the heights deemed impregnable? The Cape of Good Hope!

the pass at the foot of Mount Muissemberg, which is the only path of communication between the Cape and Simon's Bay is so well secured by the recent construction on the heights that it may now be deemed impregnable.