I would go to another dealer because this one is incorrectly advising you to replace all 6 injectors!
This also puts doubts on their analysis that you need glow plugs!
Like I said in my previous post,if you have one or more faulty glow plugs,then you will need to swap all 6,because the fault could spread to any that you havent replaced.
With regards to injectors,you will only need to just replace the faulty one.