Land Rover Repair: Help documenting bad repair, land rover dealer, land rover dealership

Question

Image showing wrong bo 2001 Discovery had head gasket replaced in 2004 due to overheating.  This year had oil leak at one bolt area.  Mechanic (Land Rover Dealership) found that longer bolt had been used where short bolt should have been used.  Made hole into cooling channel and allowed mixing of oil and coolant.  Oil leak developed after few years due to loosening of wrong bolt.  Original mechanic (Land Rover Dealer) won't acknowledge mistake was made.  I'm trying to find pictures of parts involved and a good way to explain to them why using the wrong lenght/size bolt caused the problem.  

Answer
This is a legal question, not a question for me.  You have articulated a theory of failure.  You should present that to the dealer, see what they say, and make a decision as to the next step based on the answer.

I am not sure if your theory is correct.

You say you want pictures . . . you should be able to photograph your own car, right?  The evidence is there, not in another car's photos.  If the bolts are wrong, they are wrong.  

But how did they get that way?