Door Widening for Wheelchair access

What should have been a relitively simple operation ran into trouble almost immediately. The contractor who was on site at the time, the window company came with the new door and frame, Northdowns contractor was supposed to cut the doorway to fit said door and frame.

He stated that the company who had subcontracted to him had not sent a 9" angle grinder so he could not do the job for the door firtters, NOT a problem said I, as I had in my garage a brand spanking new, still in the unopened box, a TITAN 9" cutter (I had bought this for a project that I was about to do. "Borrow mine, I have a box of cutting discs to go with it" "Sorry mate cant do it has to be PAT tested first before I can use it. Not to worry my boss said I can go and buy one from screwfix. 

Some 3 hours later he rolls up with a TITAN 9" cutter and a box of disks. So he cuts the hole and they fit the door then he starts to plaster in the doorframe using a dab and set method for pasterboard. I took a quick look and noticed that he was trying to cover, the lintle, which was now free hanging from one side (no more brick support) I pointed this out to the main contractor and then the sub contractor went and got a L shaped lintel joist to fit in so both sides of the bricks over the door would now be supported. then he stucj some plasterboard over (squint and out of line in every way. By now I had enough so went and looked at the "Nearly Completed Bathroom"