Then came the trip around the Overground earlier this year, which I decided to write up as a kind of epilogue.
Now I have an epilogue to that epilogue, in the shape of a visit to the disused Underground station of Aldwych.
It wasn't your ordinary tour of a disused station, however. This was part of a three-day event organised by the fine folks of the London Transport Museum entitled Under London, with Aldwych station recreated to appear how it would have looked 70 years ago when it became a shelter from air raids during the Blitz.
As well as dressing the station with posters and props from 1940, a small cast of character actors was also on hand to give the tour a kind of dramatic structure.
Now this might sound a bit unnecessary, even silly; but honestly, it was a masterstroke. It really was a fantastic experience, right from the outset when we were shuffled into the station ticket hall to be addressed by an authentically stoic ARP warden:
Our man did a bit of business about gas masks and what to do if we were caught short, before right on cue an air raid siren sounded.
We had to file down the spiral staircase of 160 steps to be greeted by an authentically bossy female shelter supervisor, who delivered her lines with great aplomb, switching effortlessly between upbeat banter ("Been shopping, dear? How lovely!") and downbeat prophecy ("Remember, the bomber always gets through"), along with more potty talk. Toilet training was clearly of utmost concern during the Blitz. (Tip: bring a blanket to preserve your modesty, plus some cloves of garlic for the smell).
We were then split into groups and taken on to the platform itself, where a train was parked, decked out in period advertising.
More colourful characters lurked within the carriages: a gossipy woman doing knitting, and a smooth-talking spiv who promised me two tickets to see "Snakehips" Geraldo at a local dance hall next weekend, besides asking me to vouch for the quality of the material on a pair of parachute knickers.
Yes, this was a hands-on tour and no mistake.
My friend Chris and I started wondering how they must have recruited these actors. 'Must look convincing in tin helmet...know how to handle gas mask...Cockney accent...moderate rhyming slang...jovial countenance essential'.
Smart-eyed readers will observe that the train parked in the platform was rolling stock not from the Piccadilly Line, but the Northern Line. I overheard one of the museum staff saying that this train was still in service as late as 1988. I certainly remember its wooden floors and hard-backed seats from trips to London as a child.
Aldwych only closed in 1994, but it must have been in a pretty dilapidated state even then. The walls and tunnels bear signs of decay that are depressingly long-term.
The platform was kept in darkness during the tour so it was hard to get a true sense of what it must have been like when fully operational - but in a way that wasn't the point, for this was a semi-fictionalised event, not merely a facts-and-figures tour.
The whole thing ended with a montage of sounds depicting an air raid going on above us, followed by a brief attempt at a singalong. Sadly, not many people seemed to know the words to It's A Long Way To Tipperary, but I joined in, as lustily as I dared.
Then it was back up the 160 steps (not as much of an ordeal as it sounds) and out past an array of merchandise including Ministry of Food fudge, which really ought to be brought back (both the fudge and the Ministry of Food).
I've always been intrigued by Aldwych station and to be honest for much of the tour I was walking round with a stupid grin on my face.
Hats off, or rather helmets off, to London Transport Museum, together with London Underground, for devising such a superb way to allow people a glimpse of a bit of a subterranean icon.
Oh, and on the way out we were all handed one of these: a tour guide designed to look like a ration book. The perfect finishing touch.