Large flower-tub 'saucers' for outdoors (Kingsmead BA1)

sizeable planters needing to catch the run-off after watering. 2 foot diameter needed. Not sure if any such thing exists but can make do with any flat lid that's wide enough. looking for as many as possible... 5 at 2' or a bit bigger and 3 at even wider. (yes, the tubs are quite large :-)