Many thanks - that did the trick, and I now have automated an old Echo Dot announcing (through TTS) if the solar panels trip out during daylight hours. The cookie isn't persisting, but I will investigate and hopefully sort that out today. EDITED TO ADD: Cookie now persistent
I do love the way so many technologies can be linked together to create something "useful" (debatable, I know).
OpenEnergyMonitor CT clamp
ESP8266 wifi module
TP-Link powerline adapters
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