'The allegory about the shower & the coffee percolator in Drake's cottage, which don't work before he leaves The Village but do when he returns, is often taken to mean he has no life outside The Village (http://www.theunmutual.co.uk/article24.htm), but I think could also refer to dependence on The Village authorities, a truly institutional point to make.
'The home element in this episode is actually more important than it may seem. He manages to 'escape' from The Village (albeit unknowingly with his captors' blessing), & goes home, that is to that place that represents all that is most important for everyone, right? I can't believe I've missed it all the other times I've seen this, but the house is only Number 1!' (http://culttvblog.blogspot.com/2013/12/the-prisoner-many-happy-returns.html?m=1)
That is clearly the 'received' way to understand the allegory in this episode, & I want in part to go with that understanding. On the other hand when you concentrate on the allegory here alone it suddenly becomes interesting.
If the Village represents something, then it is interesting that it is empty. Well, it isn't empty: the point is that Number 6 is there. Again it strikes me how the Village can be clearly read as his own brainchild, dream, city (with all that represents). The very fact he is left alone there implies that he has rights of access. Who has the automatic right to enter Number 2's room? Number 1, that's who.
And all this is done without intelligible (to English speakers) speech for much of the episode. It once again stresses his lack of need for anyone else. If any episode was all about Number 6, this one was.
The moral lesson for him of this episode is to lose his touching faith in the authorities, who will clearly be one step ahead of him at every point. For me this is the point at which Number 6 is no longer credible as John Drake, who surely ought to have lost all respect for his erstwhile masters in the events towards the end of Danger Man!
I have another theory. If The Village represents Number 6's own (unacknowledged & certainly subconscious) dream escape from his normal life, then his former home must represent what he *thinks* is his own persona, home, security, identity. Seen like this, the allegory is that Number 6 must enter into reality & see what he has actually done, rather than seeking the security of the wrong thing. He is *almost* deluded in his refusal to face reality. The number 1 on the door of his house almost screams: 'It's you! You're the source of this!'
Mrs Butterworth allegorically reinforces this: by being the interloper in what he thinks is his own, she loud-pedals the message that he is wrong. Then by proving to be the new Number 2, she screams this message even louder, that the Village is his own creation & dream. So se is both interloper in his (wrong) dream, & the hated authority figure in his actual dream of escape, allegorical for the fact that people often don't like their dreams when they get them.
She speaks to him cosily, almost intimately; she refers to missing her husband (well we all know what that means). I love that she approaches him in the exact same way when she brings him his birthday cake as the new Number 2. This intimacy underlines that he has himself put the figure of authority in place in The Village, whether understood as a real spies' village, or an allegory for his dream escape.
The birthday cake of course underlines the recurring death & rebirth imagery of The Prisoner. Perhaps he's actually learned the lesson, & realised something at any rate about The Village. Just as the darkness & light may (in my humble opinion) be understood best in dualist terms rather than orthodox Christian terms, so I feel this rebirth may be more like a Masonic initiation than baptism. He is almost literally blindfolded & bound at the beginning, but enlightened at the end. I feel that having escaped from a prison of whatever sort, it may not be the best idea to go to your home address - symbolic of his darkness. His trust of the authorities is also allegorical for this.
The sound track is interesting. One of the fanfares used to announce tannoy items in The Village is played once or twice. It may just be me, but this gives an impression that the whole world is The Village!
Of all the episodes of The Prisoner, this to me is the most unreal, & therefore best understood as an allegory, since there are a few major problems with the plot. It simply isn't possible to make the number of people in The Village just disappear overnight, especially prisoners with dangerous knowledge. The way Mrs Butterworth responds to this supposed complete stranger coming to her door is also incredible, & ought to have been another warning sign to Number 6. In fact the whole plot of the episode is incredible - in reality it must be easier & cheaper to keep a prisoner in than deliberately let him escape & return, but then the intention here is plainly to point to the reasons for the empty Village, events on his journey, & the return of the people on his return.
I wouldn't like any of this to detract from the original allegorical point, of Number 6 not having a life without The Village. When he goes into the world outside The Village, he can't really be sure who is who. Incidentally I love Patrick Cargill as Thorpe: he has one of those voices that you only get through smoking. The possibilities are only two: they know about The Village or they don't (they obviously do, & aren't saying). But it is another example of Number 6's 'darkness', or rather naivete, to expect to go back to the Establishment figures, in whose sides he has plainly been a thorn for years, & expect them to believe him or trust him. It is also incredibly naïve to trust them, when he himself doesn't know which side (in the Cold War) owns The Village. You cannot escape Them, that's the point.
An excellent episode allegorically, understandable in several different ways, as are all Prisoner episodes. The plot has some incredible aspects, but these are helpful to an allegorical reading of this one.