Lumia 800 update stuck?

Zune updating my Lumia 800 to version 7.10.7740.16 but has been stuck for over 3 hours saying "Don't use or disconnect your phone until the update is complete".

Doesn't appear to be stuck as progress bar graphic is moving.

Should I leave it? Is there a log file that would show the progress and if its doing anything?

Zune.exe process has average cpu use of 25% so assume its doing something......