Help required re iron staircase

Hi All,

Was hoping someone can advise me please. I've recently purchased a 1st floor flat which has a rear exit iron staircase to the ground floor. At the time of the building survey the surveyor said there was a fair bit of rust and it may need further looking into. Whether it's going to be paint, part replacement or full replacement I don't know but am hoping to get advice from a specialist. Do I need to go to a structural engineer for this? And if so, any recommendations and expected cost?

Thanks