Cheap drivers side rear arch needed or a pair if the price is very good. Doesnt matter too much about finish as they will be painted at a later date.

Hmmm... There are at least TWO different depths that I am aware of.
The Viento being the deepest (or widest!!)
Not sure if the Velocity, and Velocity XT (extra Track) and the Locost are all the same..

Best to measure and put it on your post.