Thanks for that - finally got it re-charged. In recovery mode there are many more options than mentioned in the tutorial, viz: Reboot system now, Reboot to bootloader, Apply update from ADB, Apply update from SD Card, Wipe data/factory reset, Wipe cache partition, Mount/System, View recovery logs, R...

My BV5800 screen has been locked by Norton Mobile app after I accidentally sat on it (quite gently), 5 days ago, while out on the hills - maybe the SIM card moved. All seemed to be working, just couldn't access anything through touch screen. Norton say to use the BV unlock mechanism, but don't know ...