Touch of Time Antiques has dated this Regency Porcelain Teacup Saucer to the 1800s.

Similar examples can be found in A Compendium of British Cups by Michael Berthoud –plates 745 and 746.
Both cup and saucer are marked to the reverse with pattern number 1164.
Dimensions:
Cup – 5.5 cm high (excluding handle), top diameter – 9.4 cm.
Saucer, diameter – 15.2 cm.
Condition: excellent antique condition without any damage or repair, no crazing and only minimal wear to gold (to the well, where the cup sits).
Touch of Time Antiques has dated this Regency Porcelain Teacup Saucer to the 1800s.
You can view the stock and full dealer information on the Touch of Time Antiques Profile Page