Thank you Michael. Ross Roses catalogues carried a "soft salmon" 'Carla", so I have presumed the climber was a sport of the De Reuter 1963 'Carla'. But there is a possibility that it may have been Mansuino's 1960 'Carla'.
I can't understand the Modern Roses 12 attribution of the sport to Riethmuller though. Perhaps Eric Timewell or Laurie Newman can shed some light on this.