Does anyone know if a 3.5 inch angle iron over a 12 foot span is
adequate to support 8 foot of brick wall above?

A 12 foot wide picture window was replaced in a cavity gable wall,
with the result that the outer skin of the wall started to collapse.
There's a lintel on the inner wall but the outer wall was just built
off the original frame.

The collapsed part of the wall was taken down, the angle iron
installed (I didn't see it installed but I'm calculating it's 3.5
inches as it's not the full width of the brick but the outer edge is
visible), and the brickwork rebuilt.

It wasn't inspected by BCO.

To me it looks like there's a noticeable bow in the middle.

I can see why angle iron would be used so as not to disturb the inner
skin, but it seems quite a long span, and that some sort of U-shaped
construction on its side that would allow two or three courses of
bricks to be built within the U would be required. How is the weight
of the roof factored in?

Is there a table or calculator online that deals with this? And
should it be BCO inspected?

Thanks.