I discovered a fix to this by accident yesterday. Originally I was having trouble interrogating the phone book or playing bluetooth audio via my VW Golf factory bluetooth head unit.
I read up here and elsewhere regarding the issue and discovered that short of using a custom rom that the fix might be a factory reset.
I figured it would be best to backup the Galaxy S2 via Kies and when I opened Kies I noticed there was an update, which I also completed. Low and behold the damn thing wouldn't run the backup properly and it appears ICS & Kies are also having issues!
After much frustration I discovered the fix to this was to go to
Settings> Applications> All> LogsProvider> Clear Data
Voila fixed the backup issue.
Thankfully I didn't do the factory reset this morning because when I jumped in the car the Phonebook was available via the MFD & Bluetooth Audio was also working.
So before you go ahead and factory reset try this!