Hi,
The hold down bolt, of course is stripped. I would try to apply some upward pressure on that bolt, via a large screw driver as a pry tool. Have someone else backoff on the bolt as you are prying upward. I know how tight the space is, so good luck. If this fails you have at least two more options: Access the bolt from underneath the fenderwell by removing fenderliner and splash shield assembly. This is more labor intensive than you like? Take a hacksaw blade, if you do not have one of the "mini-blade holders", and slowly cut the bolt in to. You probably want have enough room to use a regular hacksaw, much less a big ole reciprocating saw. Regards, HC2000