Back again answering my own question (should anyone else have the same problem). My problem was that I did not have the correct number of pages. I didn't realise that there had to be multiples of 4 (ie an A4 page folded in half, representing 4 pages). I went back in to my project and combined the contents of two pages into 1 page, thus reducing from 13 to 12 pages. Then went into "single page" view and deleted the blank pages. Problem solved. Hope this all makes sense. One very happy pensioner here about to celebrate with a well earned G & T!!