By Lars Mucklejohn Investors will be hoping that Natwest can shrug off margin pressures and draw a line under a headline-grabbing “debanking” scandal as it gears up for new leadership and a much-hyped retail offering. The group, also made up of Royal Bank of Scotland, Ulster Bank and private bank Coutts, is expected to post bumper pretax profits of £6bn and income of £14.6bn for 2023 on Friday, according to an analysts’ consensus. Natwest’s third-quarter results triggered its biggest one-day share drop since Brexit after the bank lowered its net interest margin (NIM) guidance. NIM is a key ind…