You raise an interesting point. I was just thinking about the insulation properties to be honest, and there's nothing on the architect's drawings about fire protection, yet they carry such detail for the steel beams over the openings to the house (which the building inspector has also mentioned).
Do lintels over doors opening generally received additional fire protection? I might be able to squeeze in some 15mm fireboard instead of the 12.5mm PB I was going to use but space is tight.