Convert from gallon [UK] to ounce [UK, liquid]

Unit Definition (gallon [UK])
Currently the British use a larger gallon than either of the American gallons. The Imperial Weights and Measures Act of 1824 established a new unit for all volumes, liquid or dry, replacing all the other gallons in previous use in Britain. The imperial gallon, designed to contain exactly 10 pounds of distilled water under precisely defined conditions, holds exactly 4.546 09 liters or approximately 277.4194 cubic inches. The imperial gallon equals 1.20095 U.S. liquid gallons (British wine gallons) or 1.03206 U.S. dry gallons (British corn gallons).

Unit Definition (ounce [UK, liquid])
The ounce [UK, liquid] is a traditional unit of liquid volume, also called the fluid ounce to avoid confusion with the weight ounce. In the British Imperial system there are 20 fluid ounces in an imperial pint, so each fluid ounce represents about 1.733 871 cubic inches or 28.413 063 milliliters. A British fluid ounce weighs exactly one ounce at a specified temperature and pressure.