Has any of the crack mechanics solved your issue? LOL. No one is going to solve your issue other than the Mclaren tech's. If you were out of warranty and wanted to DIY then what you are posting is relevant (you're going to need other people's help and even then it will be generic and a fishing expedition. If people actually told you their buying/servicing experience with Mclarens (which they won't ) then you'll know how much credibility to give them.
I haven't gone through the entire thread since the last time I posted. However, emergency roadside service with exotic cars is not an on demand service. It can take a while. Sometimes even days. Mclaren and other marques will not ship it to another dealer of your choice on their dime. it goes to the closest dealer to where the car is.
Just too much confusion being given by people on these forums.