Tidied up ScenarioModel
Tidied up ScenarioModel

- removed unused constructor

nismod/smif,nismod/smif,willu47/smif,tomalrussell/smif,willu47/smif,nismod/smif,tomalrussell/smif,willu47/smif,nismod/smif,tomalrussell/smif,tomalrussell/smif,willu47/smif