Hi Tunde - thanks for the feedback and suggestions.
I tried to render the same scene, only with no photons/GI.
It took AGES, even with lower anti-alias settings.
I wasn't sure if values greater than 0 would be ignored or not when I used GI (I wrote down in my notes that you couldn't bounce in FG),
but I just did 2 quickie renders and compared them in RAM Player:
Render #1 (test_01.jpg):
800x600
GI; 250,000 photons; FG; Min: 1, Max: 4 - Bounces: 0; Time: 11 minutes 50 seconds
Render #2 (test_02.jpg):
GI; 250,000 photons; FG; Min: 1, Max: 4 - Bounces: 3; Time: 12 minutes 07 seconds
Ram Player and render time confirms that there is no difference between a scene with multiple bounces and a scene with 0 bounces, using GI.
I have attached my exposure settings - can you suggest something that I should change?.
Since I can't BOUNCE the photons in the render, I thought I'd try to fix the shadows in Post in Photoshop.
I went into Photoshop and did the following:
Image -> Adjustments -> Shadow / Highlight
I applied a 20% value to the shadow, brightening the shadows.
Thanks for the feedback - I appreciate it.

Scene with a background inserted via Alpha Channel and Image Adjusting the shadows