Regs enquiry - how many layers of plasterboard (catnic type lintel)

[Draughtsman]

There was a dbl balcony door set into a 4m wall above this steel lintel, but no longer, it just supports floor joists these days.

Will regs want it clad with 2 layers of plasterboard? And what type and thickness?

Thank y'all kindly

 

[23vc]

if it's doing anything structural then yeah, the normal is 12.5mm pink fireline board or double normal board.