The country house of the title is Compton Wynyates, a Tudor mansion (c. 1480) located near the village of Upper Tysoe, Warwickshire, England. It has been continuously owned by the Compton family since it was first built.
Hyacinth's house address is really 117
Heather Road, Binley Woods, Coventry, Warwickshire CV3 2DB, United Kingdom.