The Deliveroo cyclists aren't brilliant, but not a lot worse than the average cyclist on the roads around London, including the presence (or lack thereof) of lights. The Deliveroo mopeds however, are about as bad as the cyclists, which is worse than the average P2W, and more of a threat when they're significantly heavier and faster than a pedal cycle.
Arguably a professional cyclist ought to be more competent than others, however that certainly isn't true of professional drivers of Private Hire Vehicles, who are definitely at the bottom of the list of competent road users.