Class 395 Achievement

Okay, so on the achievement list for the Class 395 included in the london-faversham route. the achievement "Broad experience" says "Drive the Class 395 in all 4 375 liveries:. My question is how do i change the livery of the class 395?

thank you

 

There's only one. The 4 liveries is referring to the Class 375.

 

You need to re-read what the achievement says:
London Faversham: Broad Experience - Drive the 395 and all 4 375 liveries

Drive the 395 AND all FOUR 375 liveries.