I have just checked in the About Phone menu settings, and check for downloads...Nothing!!! I'm in Vodafone too...not happy. I have read the ICS should cure the signal strength and switching between wi fi and mobile data.....
Checked using Kies, which indicates I have the latest firmware:
PDA:KJ3 / PHONE KI1 / CSC KI2 (VOD)
whatever that is.
On the phone it telle me I have Android 2.3.5
Build number Gingerbread.BUKJ3 so clearly no ice cream sandwich!
NB just read the thread title...D'Oh mines a GS2