For a bit of a change of direction (we can have both conversations at the same time, of course), I present a quote from Paul McCartney, about this song:
'Penny Lane' is a bus roundabout in Liverpool and there is a barber's shop showing photographs of every head he's had the pleasure to know -- no, that's not true, they're just photos of hairstyles, but all the people who come and go/stop and say hullo. There's a bank on the corner so we made up the bit about the banker in his motor car. It's part fact, part nostalgia for a place which is a great place, blue suburban skies as we remember it, and it's still there.
And we put in a joke or two: 'Four of fish and finger pie.' The women would never dare say that, except to themselves. Most people wouldn't hear it, but 'finger pie' is just a nice little joke for the Liverpool lads who like a bit of smut.
I suspect this was only the tip of the iceberg, as far as double entendres went. Here are a few of my theories:
The fireman keeps a portrait of a queen in his pocket. Most people assume he's talking about money, but there's another portrait often kept in a pocket: a driver's license. The fireman is gay! (Side note: I once read a myth that John Lennon sang "Baby, you're a rich f** Jew!" at one point in "Baby You're A Rich Man". This is false, of course, but I think it was actually Paul making gay jokes! Also, he likes to keep his fire engine clean. Polishing the fire engine is slang for male masturbation.
The banker never wears a mac in the pouring rain. This could be a reference to a condom, or lack thereof. (Interestingly, when seen in this light, the name of John Lennon's supergroup from The Rolling Stone's Rock and Roll Circus, The Dirty Mac, could mean a used condom!)
The barber shows photographs of heads he's shaved. This could mean pubic hair, and when Paul says "And all the people that come and go" he could mean "ejaculate and go". Later in the song, the banker is waiting his turn for a shave and a jerk, and the fireman rushes into the room after having been in the pouring rain, or getting his fix from the barber.
The poppies the nurse is selling could be a reference to selling psychoactive pills illegally.
This is much more speculation than my interpretation of "I Am The Walrus", of course, but it certainly puts an interesting twist on the song!