The line, "We'll walk upon these streets and think of little else/I won't show my face here anymore," refers Bastille uses synecdoche to represent where the speaker used to live. The streets are just the part that represents the overall town where they grew up or lived. Bastille's line, "I won't show my face here anymore," further contributes to the meaning because the speaker does not want to go back to where they came from.
The personification of streets also gives meaning to the song. Bastille sings, "I don't want them/They pull me back," explains how the speaker tries to forget and get away from their past where the bad memories are. The past tries to stay with them and talks about the streets pulling them back. The streets literally can't pull the speaker back but they serve to demonstrate how their past is lingering.
Finally, metaphor, "We have stained these walls," contributes to the meaning because their memories are like a stain on the wall. The memories won't leave, just like a stain. It is also a comparison to stains being a bad spot just like their past.