Thanks for your reply... I agree they're not all bad! I've had the T610, the W800, the K610 and the K810 prior to this W910 and I've never had issues I couldn't live with.
This W910 I have now has the latest everything on it, and it still won't work! The problem I'm having is when I make or received calls; the call connects (which can be seen by looking at the screen) but no audio can be heard - no voice, nothing. Not even a buzzing or anything, which suggests the speaker just isn't turning on when a call is made. The problem is temporarily resolved by restarting the phone, but it occurs randomly again at a later time. SO frustrating!
Does anyone know if O2 might let me have a different model?