Filled circles denote cool debris disc systems, whilst open triangles denote fits to the 3σ upper limits at 100 μm. HD 69830, having a warm debris disc, is denoted as a filled blue triangle to distinguish it from the other far-infrared non-detections. Red data points are cool-giant-planet systems, black data points are hot-giant-planet systems, whilst blue data points are low-mass planet systems.