Peter, your JHW mark is John Henry Weatherby & Sons, English. I once had a double handle gaudy willow cup by this maker, but sold it years ago. The Union Jack mark dates from 1892+ and that mark usually had the pattern name above the flag, e.g. "Willow". I thought my mug was more 20th century (1920s-30s) so in guessing, you might say your pieces are early 1900s. I am not sure if the company still exist now but as recent as the 1990s the company was producing hotel ware.
Jeff