GUNTER'S TEA SHOP

Gunter’s Ices

Where did one go for confectionery in the Georgian era? Why Gunter’s of course. Originally known as The Pot and Pineapple, it was founded in 1757 by an Italian pastry-cook, Domenico Negri at number 7 Berkeley Square in the center of the upper-class, West End of London. Negri served a wide range of sweet and savory foods and was one of the first confections in England to establish ice cream and water ices as a sought-after delicacy. His elegant trade card listed such delicious confections as Cedrati and Bergamet Chips, sugar plums, biskits, marshmallow, wet and dry sweetmeats and ices, fruits and creams made in the traditional Italian style. 

In the late eighteenth century, James Gunter took over ownership of the Berkeley Square premises and renamed the business Gunter’s. The name quickly became synonymous with the finest pastries, sweets and ice creams. Every society host or hostess went first to Gunter’s when catering for a large dinner, important ball, or party.

They offered an extraordinary range of ice and ice cream flavors: Jasmine, elderflower, orange and lemon, pistachio, burnt filbert and Parmesan.

George III bought his buns there and the aristocracy of Mayfair lounged outside on hot days cooling themselves with his ices.

In the nineteenth and twentieth centuries, Gunter's became a fashionable light eatery in Mayfair, notable for its ices and sorbets. In 1815, James sent his son Robert (1783–1852) to study the confectionary trade in Paris. Robert assumed sole control of the business following his father's death in 1819, and took on his cousin John as a partner in 1837.
Gunter’s had a vast icehouse in the cellars under the shop. In 1827, they offered famous fruit ice cream thanks to the arrival of the ship Platoff with a cargo of ice brought from the sea off Greenland. Gunter’s enjoyed royal patronage throughout the nineteenth century. 
Several confectioners employed by Negri and Gunter's employees wrote cookbooks with significant chapters on icecreams. William Gunter himself wrote an entertaining and humorous book about ices, filled with asides on gossip and name-dropping and helpful tips about exercise, digestion and the stomach.
When the east side of the square was demolished in 1936–7, it moved to Curzon Street. The tea shop closed in 1956, although the catering business continued for another twenty years.

Sources: Georgette Heyer's Regency World Jennifer Kloester

Wikipedia 

Secret London by Andrew Duncan

Of Sugar and Snow: A History of Ice Cream Making by Jeri Quinzio

Further Reading:

Gunter's Modern Confectioner: A Practical Guide to the Latest and Most Improved Methods for Making the Various Kinds of Confectionery, Including Ices; Adapted for Private Families, Or Large Establishments. William Gunter, William Jeanes. Published 1875.