Also whilst on the topic of signals, the last couple of days I've been having problems where I can hear them but they can't hear me in calls. (I hope its not the OS bug some have reported on some OS's)
Here is the text that Vodafone texted me to follow:
"Dear Customer,
Press the BlackBerry key
Scroll to Options, press the Trackpad
Scroll to Mobile Network, press the Trackpad
Scroll to Network Selection Mode, press the Trackpad
Scroll to Manual, press the Trackpad Select any network apart from Vodafone and Press "" continue""
Press on Scan for available networks and then select Vodafone
I initially thought it was the O2 outage but just seems a coicidence.