This provided additional information that helped to narrow the search:

        We now knew that at least one of his forenames was Grenville or Granville

        He enlisted before mid January 1915

        He joined the East Yorkshire Regiment. 

        And of course, we know he died during WW1

A search of the comprehensive Commonwealth War Graves Commission database of WW1 deaths for names with Grenville/Granville Bennett produced the following four possibilities.

So Robert Granville Bennett appears to be the most probable but his first name is Robert? Further research into his family has shown that both he and his father were keen golfers and, as can be seen from these items in the Hull Daily Mail he appears to go by the name of Granville Bennett.

If he lived in Goole, how could he be listed as a parishioner of Patterdale on Mrs Marshall's list?

The Bennett family were moderately wealthy, as Granville's father Herbert was the son of John Bennett who established and was Chairman of the Bennett Steamship Company of Goole, which by 1899 had six ships operating between, Goole, London and Boulogne. Both Herbert and his son were keen golfers and members of the nearby Rawcliffe Park Golf Club which was formed in 1900 - Granville is reported to have had one of the lowest handicaps in the area. There are many newspaper reports showing the results of matches they played but Granville's name is absent from results published after February 1912, which could indicate that he had left the area. Some of the obituaries say that he was pursuing a profession in farming. William Hibbert Marshall of Patterdale Hall, who owned very large estates in Cumberland, Westmorland and Yorkshire was born at Enholme Hall near Patrington, east of Hull, and other members of the Marshall family still lived in the area. The Bennetts and Marshalls may well have had similar social circles (such as golf, the Chamber of Commerce, etc), so it is possible that he was invited to spend time as a guest at Patterdale Hall to study farming on the Marshall's estates. This of course is speculation - it would be nice to find some hard evidence that he was in Patterdale between Feb 1912 and Aug 1914. Penrith Golf Club were unable to find any records of him playing there.

Perhaps the Marshall Family archives/papers may contain some evidence of his visit, or even about the war memorial list itself.

Another possible reason for Granville being in the dale, was provided to us in January 2024 by Rosemary Stevenson, a descendant of John Bennett. Rosemary explained that Minnie Taylor, a sister of Granville's mother Mary, had married Thomas Bownass, the son Robert and Mary Bownass, who had built and owned the Ullswater Hotel in Glenridding. Census records show that, as well as running a prestigious hotel,  the Bownass family also farmed. It therefore seems quite likely that Granville was staying with his Aunt and Uncle and perhaps helping with the farming activities.