Rafters in Ridge Steel beam help

[John D v2.0]

you're paying your structural engineer to design this for you (and guarantee the design) so it is going to be hard to redesign it yourself and convince the BCO of anything.
Why not put your concerns to the SE who will be able to work with you on a new design which will also be safe and compliant, and meet your aesthetic and budgetry goals as far as possible.
All those details on the drawings are there to keep your roof together. Good luck!

 

[noseall]

Insulation board added to bottom of rafters, Insulation added between rafters, Battens will be added and tiled. Is this a cold roof?

Yes. It will need venting. We use overfascia vents as in our latest vaulted jobby...

[GALLERY=media, 107956]Bolt3_LI by noseall posted 27 Apr 2022 at 6:42 AM[/GALLERY]
[GALLERY=media, 107955]Bolt2_LI by noseall posted 27 Apr 2022 at 6:41 AM[/GALLERY]
[GALLERY=media, 107951]Bolt1 by noseall posted 27 Apr 2022 at 5:58 AM[/GALLERY]
[GALLERY=media, 107954]Bolt4 by noseall posted 27 Apr 2022 at 5:58 AM[/GALLERY]
Woody, take note of the framing above the window opening. Zero lintel (outer course) and some robust 4" x 2" 'cradling' sandwiched above the soffit ply - ideal for any upward window/door fixing.

 

[^woody^]

Zero lintel (outer course) and some robust 4" x 2" 'cradling'

Timber lintel then?

 

[noseall]

Timber lintel then?

Yes I guess it is only it's only carrying itself (nowt above) and assist the soffit and frame fixing.
The trick is (especially with wider openings) is to temporarily sling fix it to the underside of the rafters prior to fitting the soffit and fascia. Otherwise you won't get it in. You then remove the screws and drop it into place.