No real idea, but think the WWI term is shell shock, therefore Back in the Village?
It possible also works for clue 1 the connection to Prisoner, clue 2 a village could have a barnyard?, clue 4 works I think, no idea of a connection to anything else
Back in the Village is correct! Your turn.
Here are the explanation to the clues:
Clue 1: This song can be described as a combination of two other Maiden songs in terms of theme, but also the mood of the lyrics.
The song obviously shares a common origin with The Prisoner, namely the Prisoner TV series (several references to the Prisoner series: The Village, I don’t have a number, I’m a name, I see sixes all the way), but also Aces High, as it adds some flying references (drop your bombs, in a black hole and I'm spinning, as my wings get shot away), delivered by Bruce in a manner similar to Aces High.
Clue 2: The song points to a location within which one can find a place with the same name as a studio facility used by Maiden.
In The Prisoner, "Number 6" is incarcerated in a place called "The Village". The series was filmed in the Welsh model village Portmerion. There, you'll find Battery Square in the town centre. Maiden’s first three albums were recorded at Battery Studios, London.
Clue 3: To elaborate on clue one: Also the overall idea of the lyrics clearly relates to a sort of reappearance.
Back in the village (again).
Clue 4: Parts of the lyrics are without a distinct narrator, but the chorus of the song is narrated in the first-person singular. Yet another section of the lyrics applies the first-person plural point of view.
Self-explanatory.
Clue 5: A famous, wall-mounted message is quoted in the song, although not verbatim. The message also has a link to one of the songs in clue 1.
A wall sign in an office from the Prisoner read: “Questions are a burden to others. Answers are prison for oneself”. Also of course related to The Prisoner (song).
Clue 6: The opening line contains a phrase that can refer to guzzling a specific type of liquor.
“Eat the Worm” is slang for drinking tequila.
Clue 7: The song can be heard with different endings.
For some reason, the 1998 CD reissue of Powerslave moved the intro section to the song Powerlave to the ending of Back in the Village, hence making the song longer than it originally was.
Clue 8: The song contains a word that came into sommon use during the first World War, after an article written by a London-born scientist. By WW2 the British Army had stopped using the word because of its inaccuracy, and the condition the word refers to currently goes under another name. But the original term had already been well established in the English language, and found its way into this Maiden song.
"Shellshock", coined by psychologist Charles Samuel Myers in a 1915 article. Later replaced by more precise, yet less catchy terms, such as PTSD.
Clue 9:
A shot from Supergrass' promo video to their biggest hit, "Alright", which was filmed in Portmerion and features many of its iconic views.
Clue 10: The song does not apear on a Maiden single. To elaborate a bit on clue 9: The link to the Maiden song is to be found via clue 2.
Self-explanatory.