battery tray - broken studs
 

Hi !
I traced a rattle coming from the front firewall to the battery. I noticed that two of the three bolts were broken (probably turned off when the nut was rusted).
:mad:
Anyway, I can replace one (at the front) as it is on a raised plate that can be reached easily.
The other one fits directly to the body.
If I replace the broken stud with a bolt and nut (as on the raised part in the front), how will I reach the location of the stud that's on the body? I connot tell where to rach the bottom from ...
Any pointers, please?
TIA
L