But if there is a dual carriage way, as in the example, the lanes will very likely be wide enough to accommodate both car and bicycle ... especially in my part of the world where the law I referred to comes from.
As far to the right as practicable means riding as close to the curb or edge of the road as you can and still be able to pedal the bicycle without running into road grates, gravel, etc. Should you encounter such hazards, you are allowed to move toward the middle of the lanes.
Interestingly, the law here also states that motorized vehicles should ride as close to the center line as practicable.