I cleared the cache and the user data and re-flashed the Xolo ICS update.zip. I then checked the OTA update screen - which now had the two blue boxes at the bottom - and did the OTA update. It told me I needed a 57MB update (if I remember right) which I agreed to. It rebooted with fully functioning video.
I've got the Xolo update.zip (299MB) installed but have the no video on the phone problem. I can see the display OK either via HDMI cable and the TV, or via via the VNC option.
When I try to do an OTA update, I get the update screen OK, but all it has is a small orange box in which you can put a tick (or not). The two blue boxes at the bottom are missing so the OTA update doesn't work.
I have tried to root the phone with the AZ210 tools, but no success: the system is read only.
It won't flash back to the original Orange system, by the way, so I'm well and truly stuck!