Hi Mike,
The inside were ground back to shiny metal and the copper coloured substance is some sort of rust killer, he did tell me the name of it, and then over that is the black protection coat
. They cut the entire jacking points out and started again, hence they look a little different and stronger than the original.
Here is the infill panel welded into the arch. Time will tell if they have done everything they have said they would but just like every other trade now to a certain extent you are in their hands.