Scene Fade in and out script not working

Hi all, I am following the Stealth Tutorial and using the Fade In/Out script for my game.

Tutorial is here: http://unity3d.com/learn/tutorials/projects/stealth/screen-fader

The problem I am having is that when the level starts, it fades from black to clear absolutely fine, but when I call the EndScene() function, I see the GUITexture enable, but then it doesn't change the color, its almost like the Lerp doesn't ever kick in.

Here is the code I am using:

 using UnityEngine;
 using System.Collections;
 
 public class SceneFadeInOut : MonoBehaviour 
 {
     public float fadeSpeed = 1.5f;
     private bool sceneStarting = true;
 
     void Awake()
     {
         guiTexture.pixelInset = new Rect(0f, 0f, Screen.width, Screen.height);
     }
 
     void Update()
     {
         if(sceneStarting)
         {
             StartScene();
         }
     }
 
     void FadeToClear()
     {
         guiTexture.color = Color.Lerp(guiTexture.color, Color.clear, fadeSpeed * Time.deltaTime);
     }
 
     void FadeToBlack()
     {
         guiTexture.color = Color.Lerp(guiTexture.color, Color.black, fadeSpeed * Time.deltaTime);
     }
 
     void StartScene()
     {
         FadeToClear();
 
         if(guiTexture.color.a <= 0.05f)
         {
             guiTexture.color = Color.clear;
             guiTexture.enabled = false;
             sceneStarting = false;
         }
     }
 
     public void EndScene(int leveltoLoad)
     {
         guiTexture.enabled = true;
         FadeToBlack();
 
         if(guiTexture.color.a >= 0.95f)
         {
             Application.LoadLevel(leveltoLoad);
         }
     }
 }

Any ideas as to why this might not work?