Having reviewed the lunch/dinner offerings in the Concorde Room at Heathrow, I am covering their breakfast offerings, available to noon. The menus are located on tables around the Room, and if you choose to sit down they will bring one.
There is a wide range of cooked items available, although I tend to stick to toast. Especially as they can usually locate some Marmite, and I do love toast, butter and Marmite.
On my last visit the room was fairly quiet, and service was prompt and friendly as I have found it to be recently.
People complain that the staff can be hard to attract for service. I have found that if you locate one, place a clear order, then they bring what you need. If you are there for a little while, they regularly check whether you might need more.