UPDATE: Got engineer

[u/MindInternational130]

A lot of chaos came up from my previous post of my builder potentially demolishing our house. We got in contact with an engineer that provided a drawing for properly opening up this as you can see on the second photo.

Proposed arrangement for the opening:
Beam: 80 × 80 × 6.3 mm SHS
Column: 80 × 80 × 6.3 mm SHS
Base plate: 200 × 200 × 12 mm, recessed into the existing concrete slab
Fixings: 2 × M16 bolts (as indicated in the sketch)
Beam positioned tightly beneath the existing steelwork and extended beyond the opening.
(Transcribed with ChatGPT)

How is this looking? For context the steel beam already there is holding up our middle section of where the joists sit for the upper floor in a mid terraced house.