Now the authentication problem with various Alexa nodes has been sorted I thought I'd try something new.
I used BluePrints to create a Q&A skill called 'Give me a status report' then linked that in the flow below.
I've arranged for various devices around my home to report their status to a database that is accessed from the flow and sent to the appropriate Alexa device. Here's an example of capturing feedback from Sonoff-S20 switches and writing the status to a dB.
The whole thing turned out easier than I thought it would - and works really well.
So now I can say... "Alexa... give me a status report" and guess what she says???