Gilbert Adair - And then there was no one

Taken in context this is an extraordinary book the third in an Agatha Christie pastiche series, it defies categorisation. It is the book that shoots the golden goose but perhaps that is Gilbert's intention. The first 2 books , Act of Roger Murgatroyd, and A Mysterious Affair of Style: A Sequel are all part of a supposed Evadne Mount Trilogy. The first two books in the series were hilarious pastiches of Agatha Christie. (I listened to them on CD in the car and was nearly crying with laughter in places!) In them we had a completely over the top sleuth in Evadne Mount.
This book is nothing like the others. It rambles, it makes 'clever' diversions into art and literature and plagerism. It educates us on Sherlock Holmes, authors and literary festivals and the US post 9/11. There is a murder but it is inconsequential.
For the first three chapters I defy anyone to work out what is going on. To be honest I could not decide whether this book was clever or was just selling itself as such. All I do know is that I felt vaguely unsatisfied at the end, and very nearly gave up half way through, but then perhaps I am too simplistic! I have seen reviewers calling it Postmodernist, whatever that is, I am still confused!