Anyway, for the purposes of the session, I created a dummy book with which to experiment and with Catrin's help, figured out exactly how a back-to-back binding works. Here are the results and I'm very excited to finally have a clear idea of how this book is going to look.
My intention now is to use what is called a 'quarter-binding'. This means that I will be using book cloth on the spine and the rear with a printed image which will take up three-quarters of each of the covers. Don't worry ... It will all make sense very soon now!!!
I have now ordered some gorgeous book cloth in various colours and one or two other lovely bookbinding goodies from these people http://store.falkiners.com/store/ Have a look at their website if you are at all interested in bookbinding and paper. They have some beautiful things and the service is excellent.
Next step? Finalising the cover design ...