With my sons help...
We unbolted the lower latch pictured above... the rod had become disconnected at both ends, so we pulled it out.
I unscrewed the carpeted side trim and levered up the wheelarch area to get at the upper latch.
Somehow... my son put a long screwdriver into the dark void and by looking with a penlight managed to push the latch up and release the seat!
YEAH!
We then removed the side trim and swiveled it out of the way.
The upper link plastic clip was good, but the lower was broken... we cheated... I threaded the rod end and put a nut on it... so it wont come off again!
We felt very pleased with ourselves!
Thanks for all the help guys!

__________________
2009 Mercedes ML320 Bluetec