However, whereas using bq's Ubuntu 15.04 OTA5(?) allowed me to at least browse the internet, but little else, I now have the original problem back. The bq appears to connect to the WiFi but I cannot get a network connection, so no updates, no browser etc.
I've tried 2 different WiFis and have performed a reset. (Settings Reset Erase and Reset all.) This has made no difference as neither WiFi will work. Although it says it has connected to my Bluetooth keyboard, it has not given a code to type and the keyboard isn't working with the bq10. It seems that the wifi and bluetooth issues are connected.
Is there a WiFi/bluetooth I/O problem with the OTA 8 & 9 and the bq M10 HD? Is there anything else I can try?
Edit. Reading wifi bqm10 it seems that this is an old, but unsolved, issue. However, I don't understand why wifi worked well for months then suddenly stopped. Only installing bq's original Ubuntu did I get it back, but that is such a limited OS.
Edit 2: I can connect through a third modem, a mobile MiFi, so I'm up and running. Thanks for all your help.