Radial distance, r, from the centre of the Sun of CME-driven shocks associated with LDGRFs at the peak times (circles) and end times (squares) of detected γ ray emission. Constant deceleration is assumed during propagation, as given by Eq. (8), and initial plane-of-the-sky speeds were taken from the SOHO/LASCO CME catalogue. Each shaded wedge spans 500 km s⁻¹ increments in radial shock speed between 500 and 3000 km s⁻¹. For the 2012 March 7 event we show two sets of radial positions for two different CME-driven shocks that day: 2012-Mar-07^(a) is the earlier, faster CME with a speed of 2684 km s⁻¹ and 2012-Mar-07^(b) is the second, slower CME with a speed 1825 km s⁻¹.