After my last post about the electricity supply, things improved. The lights remained bright in the kitchen and my UPS seemed happy with the voltage it was receiving.
This morning though, the electricity tripped out (again). After I reset it, I found out the voltage was the probable cause. My UPS is again signaling a drop in voltage and the lights in the kitchen are dimming.
Although it has settled down again, I'd be interested to know if others were experiencing the same problems and why it is happening.