Change material on imported object

Hi, I'm trying to apply a material to an object i've just imported.

The object currently has '01 - Default' applied to it, I'd like to assign a different material to the model. I know I can apply a material to the object when it is in the viewport, but I'd like to permanently change the object's material instead of adding the material every time I bring the object into my scene.

Any help on this would be appreciated.