The plumber has called and he has fixed the faulty part in the pump control mechanism - so the water tank is starting to fill up again. Relief!
The insects zooming around the pond were none the wiser, thank goodness, disaster averted. I have finally managed to get a snap of the big turquoise Dragonfly as he was soaring around the big yellow digger - somehow reminiscent of 'Diving bell & butterfly'? Also the yellow Damselflies have taken a liking to the reed that grows next to the big rock.