Lintel for Bifolds

hi,
I have a set of french doors I want to replace with Bifolds. This will extend the opening by around 900.
The French doors are in a single story lean to extension, there are no bricks above the French doors, it seems that the builder put a roof plate across and then the roof timbers are sat on that.

The lean to roof hits just under the upstairs window.

So would I need to put some kind of lintel in, or just use the wall plate?

When I looked into bifold, I was told that a steel was needed to support the doors.
So your roof would need to come off unless you can source a set of bottom runner bifold?

Mine would be bottom runner, told never to have top runner ones