RCO Tutor Gerdi Troskie teaching a class on twentieth-century organ repertoire, on the Kenneth Tickell organ in Lincoln's Inn Chapel.   StopPress Editor Morwenna Campbell-Smith took up organ-playing as an adult beginner in 2013.  Searching online for an organ teacher, she found the RCO Summer Course and bravely booked in as a complete novice. This summer, twelve years on, she decided to attend the course again: though this time not as a beginner but in the 'Towards ARCO'  strand.  Here is her account of two busy weeks, twelve years apart.   The big RCO Summer Course…