Fitting Lintel (RSJ) and Bifold doors

[Bug-er]

Hi

I'm researching into how to complete the next part of my current renovation project. I have done building tasks in the past, built garages and extension but I have always avoided any lintel work. Unfortunately for this latest task I need to face this fear! Hence I'm here asking for help and advise.
I have building control approval and I have had a structural engineer calculate and specify the steel required. Images below. The floor joists run left to right on the rear wall so supported on the side walls not the rear wall.
Any advise on how to support the wall etc?I understand the options are acros and strongboys but what quantity and where? I have also seen a brickymate which supports walls during work are these any good?
I assume I will need to break away ceiling inside the house to support the inner wall skin abouve where the box section of the rear beam will go.

Thanks

 

[^woody^]

Under CDM Regulations, your engineer should be providing your with a method statement to detail how the wall should be supported and how his steel work is to be installed.

Typically you need props inside and out at max 1m intervals.