"The Soldier's Rest" by Arthur Machen

Wells being a cathedral city in Somerset county, not far from Bath and Bristol.

Cambrai - I didn't even attempt the French pronunciation here, given how awful my attempts at French are. But when Anglicized, it appears there are multiple accepted pronunciations? Maybe? I don't know, it's all very confusing to me trying to figure out how to pronounce this city name.

Arf a mo' - I had no idea what this meant, but the almighty oracle of google says "half a moment". Apparently most famously on a 1914 poster of a British Soldier lighting a pipe saying "Arf a mo', Kaiser!"

"Opening of Parliament by the King" - given this story is set in WW1, this would be King George V. Who had become king only a few years before the war, in 1910. And would remain king until a few years before the next war, in 1936. And he legitimately looks like a twin brother of Tsar Nicholas II of Russia. They were related, being first cousins, but they seriously look like twin brothers.

Vin nouveau du Royaume: Possibly this is a reference to Matthew 26:29?

I'm not entirely clear what the last lines are supposed to be a reference to. Perhaps the Prayer to Saint Michael the Archangel? Although that's typically more a Catholic thing, and of course British soldiers are more likely than not to be Anglican. And technically Machen was Anglican, although he seemed to have a liking for Catholicism, so I would expect he was plenty familiar enough with the prayer, especially after the start of the Great War.

The picture used is a Greek Catholic icon of the archangel Michael. The angel holds a flaming sword in his hand. The icon was painted in the end of the 18th century as part of the iconostasis of the Greek Catholic Cathedral of Hajdúdorog, Hungary. Michael is depicted on the northern Deacons' Door. Photo by Jojojoe, used here under the Creative Commons Attribution-ShareAlike 3.0 Unported license (https://creativecommons.org/licenses/by-sa/3.0/deed.en).

To follow along: https://web.archive.org/web/20120414102251/http://ebooks.adelaide.edu.au/m/machen/arthur/angels-of-mons/chapter2.html#chapter2