Thank you to the TT user who gave me the heads up with this one!
This trophy can be found in Chapter 10: Midtown. You will have to progress the main story until you have to sneak into the club that the bouncer is guarding. To do this simply go round the back and do some cat parkour and jump through a now open window! Once inside you should see these two DJs on the stage playing tunes for the entire club.
Stray
There is a table to the back of the room that has a vinyl laying on top of it, you want to pick this up and take it over to the DJ station!
Stray
Jump up onto the DJ station and you should be able to see the prompt appear on one of the vinyl. Drop the vinyl onto the deck and then the prompt to scratch should appear. After doing this you will earn yourself a lovely little bronze trophy!