just booted and tested it was working OK with old version of S/W. It was fine. Rebooted and updated the stable build only from noobs, started downloading a little, gave an error, sorry cannot remember what, and died. No LEDS on removing and replacing power, not even the slightest flash that I could see.
So I decided the only course of action was to follow the "bricked recovery" instructions, which worked fine. Now running nightly which is fine too.