Are there any GSM network specialists here?
The background is this:
The Nokia 808 has a "HSPA bug" which causes the phone to crash on HSPA connections, especially if the signal is weak (i.e. the phone has to use a lot of power to transmit).
Nokia's "solution" is to
disable HSPA 
From the mostly useless
Nokia user forums, it looks like after 35196505191xxxx they fixed them.
But there is too little feedback.
One interesting data point is that all 45 reviews on amazon.co.uk (almost the sole seller in the UK since Nokia don't sell it here so all are grey imports) do not mention this bug, so it looks like UK networks don't trigger it.
I wonder if UK HSPA gear is configured for a lower speed than in say USA or Germany.