We present an algorithm for the decentralised navigation of multiple mobile robots. Completely decentralised Navigation Functions are constructed, creating a potential field for each robot that gives rise to a feedback control law. The construction of the potential field incorporates limited sensing and explicit prioritisation in the form of priority classes. A non-circular sensing area creates asymmetrical sensing by reducing the influence of robots and obstacles behind each robot, introducing implicit priorities resembling "rules of the road". Static and moving obstacles are also taken into account, as well as malfunctioning robots that are unable to maneuver. A decentralised feedback control law based on the gradient of the potential field ensures convergence and collision avoidance for all robots, while respecting a lower speed bound. Simulation results demonstrate the efficacy of the proposed algorithm.