Stainless steel cold bridging & best insulation method

[Osman]

I have stainless steel beam 100x100 installed as a U-frame to support a mono-pitched roof above a bay window, I am seeking advice around insulating the stainless steel. The stainless steel is sitting in a 100mm cavity (brick outside and dense blocks inside with PIR cavity insulation). The brick will go up half way the steel, then a window will be installed so part of the steel will be covered by the window frame. The build is in progress and I am seeking advice to what best approach to avoid any issues, what insulation is best used, and how. all thoughts are appreciated.