James Mitchell   'With this book in hand, no composer need ever again write badly for the organ!' says John Rutter, in his foreword to James Mitchell's The Pipe Organ, A Composer's Guide, just published by OUP. Rutter points out that most solo organ literature down the ages has been written by those who play the instrument.  Now both organists and non-organists can understand what makes good organ writing, with this concise and very readable manual. In 2020, as the covid pandemic kept many musicians from their playing work, the RCO promoted a composition competition, for…