Assassin's Creed Syndicate

To get this trophy, you need to complete missions for each of the following associates until you hit Loyalty level 1 with all of them. In most cases this only requires a few missions.

Henry Green (Gang Strongholds, Templar Hunts, Gang Wars)
Frederick Abberline (Bounty Hunts)
Clara O'Dea (Child Liberation)
Robert Topping (Fight Club, Races)
Ned Wynert (Cargo Raids - boats, trains, carts)
Winston Churchill (WWI Spy Hunts, Spy Hideouts)

You will unlock the first three by proceeding with the main story. Robert Topping is marked with a T on the map (he becomes available relatively early on in the story) - visiting him will unlock his events.

Ned Wynert is marked with an N and becomes available during Sequence 4 once you destroy the serum factory. Unlike the others, Wynert's events don't always sit on the map permanently, and tend to trigger when you are nearby (at least the cart raids). However there are normally plenty of boat raids / smuggling boats available on the Thames.

Winston Churchill doesn't become available until Sequence 6, and can be found, along with his side missions, in the WWI simulation accessed from the very Eastern edge of the river Thames.