in haste, as about to hie myself to London via shower and frock ...

... I read 'invented friend' as implying that he had created their friendship, as 'creative nonfiction' (which has got him into trouble before).

I also need to reread the ending (tricky, as book's gone back to library!) because I didn't pick up on the 'after you're dead' thing at all. Though I suppose that final meeting could be read as afterlife!