Your link doesn't say anything about him working the day he was arrested. He worked a relief shift on the 3rd... 2pm till 8pm. I am Guessing this is an extra unplanned shift. Seems he finished work at 7am on the 3rd and back to work at 2pm till 8pm the same day (day of disapearance)That's the shift he worked when arrested. He actually worked a different shift the day of the kidnapping. Quoted in the news. My source is
here: Timeline of Sarah Everard’s disappearance