Demi-Hunter Pocket Watch

This is a gold pocket watch that my now deceased father won when he was only 17 years old in England. It is a 24 hour movement that is still very functional and accurate. The face says DIMRA for a maker. Is that a correct name for a maker? The case says Dennison and on the backing that protected the movement, the case says "English Make / This case guaranteed to wear 10 Years" with the number 313358 on it. The chain is a double clip/double strand Royal Albert 9 carat marked on the clips and the T-bar.
The watch is an heirloom and any more info about the maker or movement would be appreciated. Thank you.