Mike,
I think maybe when the rule referred to "between the road and dyke holes" it was referring to "holes" in the old sense of the actual location of the holes in the ground, or the green. If you look at map or aerial, the corner of the hotel is situated between the second green and the 17th green.
In other words, I think perhaps the Station-master's garden was the hazard predating the Hotel (and sheds in between.)
From Hutchinson's Golf, 1902:
. . and are coming to that dreaded seventeenth—so near the end, and so dangerous! For after we have piloted our way through, or round, or over the corner of the wall enclosing the Station-Master's Garden, and the little bunker on the left, and have turned up towards the right, with our seconds, then we see that little Garden of Eden—very different from the river so called—where the hole is, lying between Scylla and Charybdis (a dread vision such as may excuse any anachronism in our similes!), that horrid little round bunker to one side of it, and that hopeless hard road on the other. And the canny golfer we see approaching it in instalments, and the bold spirit, taking his fate in his hand, going for glory or the grave.