Hi Rob, are you able to detail what bugs you have been receiving? I had issues with the messaging and also error message telling me charging paused voltage too high but only when it was not plugged in charging. As always Vodafone blamed this on Water Damage
Android 4.0.4 has been released but not for the S2.
Also users were reporting signal issues on 4.0.4.
Like NDJ said, some "bugs" are got rid of by a full factory reset and then restoring apps to your phone.
Most bugs are in the apps though, as some are still not optimised for ICS (I've had a few rants about this so won't bore you!) depending on what apps you really need they may work better on Gingerbread, the roll-back procedure is quite simple.
Sometimes the simple answer is overlooked because it's technology that's complicated!
Main problems i seem to be having are that the 'vibrate only' option does not work when i select it i get no vibration but vibrate works on full sound. Other problem is the screen freezing up etc. Ive already done the factory reset several times. It hsnt fixed the issue.