[2] In May 2015, unit 375301 was moved from Ramsgate Depot to Derby Litchurch Lane Works for a full refurbishment.

On 16 May 2015, it was returned to the Kent depot wearing a new livery, similar to, but not based on the 'Highspeed' livery carried by the high speed Class 395 EMU, with a more vibrant shade of blue on the saloon doors and bolder stripes to highlight First Class and Disabled areas.

The existing seat covers have been retained, but were dry cleaned to provide a brighter, cleaner interior.

[5] The final 375 to receive the refurbishment and gain the new blue Southeastern livery was 375 920, which was returned to Ramsgate depot on 28 April 2018.

[11] Units 375311–375338 were transferred to Southern, converted from Tightlock to Dellner couplers, and renumbered 377301–377328.