Garages are in the business to make money.
As soon as they come across a job that is more bother than it is worth, then they will body swerve it.
The 350 roof faults are not the easiest to diagnose correctly and fiddly to fix.
It is a specialist repair, however finding one who is prepared to take on the job may be difficult and almost impossible to find if you want an estimate.
I am afraid that it is one of those jobs that will take as long as it takes so you are basically giving the garage an open cheque book.