Gus Unger-Hamilton

In this picture, Gus can be seen playing a Nord Electro 3.

On Novation's website, it states that Gus has used a Novation UltraNova.

gus can be seen playing this Yamaha Motif keyboard throughout the video

In the Song Exploder podcast, Gus admitted to using a Casiotone keyboard on the "pipe organ" setting for In Cold Blood

You can see Gus using it in this video.

In this Podcast deconstructing Alt J's song the keyboardis Gus says he used this Casiotone keyboard on the song

In this Sound on Sound article it says Alt J used the Juno 6 on their album An Awesome Wave

According to Novation's website, gus uses the Impulse 61.