There was a null pointer exception related to going into/leaving third person camera and the arrow annotation.

racevisionGame/src/main/java/visualiser/Controllers/RaceViewController.java

@@ -441,9 +441,12 @@ public class RaceViewController extends Controller {
 
     private void removeThirdPersonAnnotations() {
         viewSubjects.remove(nextMarkArrow);
+        if (arrowToNextMark != null) {
             arrowToNextMark.stop();
         }
 
+    }
+
     /**
      * Swap the colour of the next mark to pass with the last mark passed
      * @param leg boat has started on