I have done a lot of research into this and have tried everything i can think of so let me run down the list of things i have done and tried.
A. Custom light map that has been snapped to a 64 x 64 uv grid.
B. Separated the back faces that will be receiving no light/or darker light from the front faces. To A. further reduce light bleeds and b save on light map res
C. Maxed out light mass settings
D. Did a production build
E. Turned AO off.
Im at my wits end and i have a client deadline fast approaching any help will do!! Thank you so much in advance.