nameless places

I remember asking John Mackin once, what would he like me to get him from London? He replied, A book from an occult bookshop which is on a street which appears on no map. It is near the British Museum.
I went to London, and asked my father. Ah!, he said. I know where that is.

When I was much younger, my father drove me along a street of nameless Georgian terraces, and said, Look at that house. If you ever need an address for a house which does not exist, that is the house you should choose. Even though you can see a house, there is no house there. It was removed so that a train line could be built for the expanding London rail network.

I looked at the house, with front door, windows, roof and front garden.

Accordingly, I have a memory of an address but no memory of the address.