Plugged iPhone into Mac at 18:05 hrs. iTunes started automatically, but iPhone did not synch. Manually downloaded software. Started downloading software at 18:06 hrs. It took five minutes to download 230.1mb file.
Install then started. Install was then verified followed by a firmware update.
After firmware update message box appeared on iTunes saying "Leave phone alone" whilst phone rebooted. Did this. iTunes picked up that phone was there but came up with error message " Could not connect to this iPhone because an unknown error occurred".
iPhone rebooted itself and started okay this time. This time my phone has changed language and is now in Japanese!
Update process took 24 minutes (even if my phone now thinks we live in Japan)