IPhone :: A2DP Audio Drop-outs Since Ios5.1.1?

I have Sennheiser MM400 Bluetooth headphones and a Bose SoundLink Bluetooth mobile speaker. Both of these worked well with my iPhone 4 (before 5.1.1) with good range and only the occasional dropout when the phone was moved. However since 5.1.1, there has been a massive reduction in the stability of A2DP audio streaming. With the SoudLink the range has reduced massively to a few feet (6 max) with line of sight and the audio drops out if anyone passes between the phone and the speaker. With the MM400 Headphones the situation is even worse. Even with the phone in my breast pocket and only few inches from the headphones, the audio drops out every few seconds. Just placing my arm between the iphone and the headphone causes the audio to drop out completely. As I said before, this did not happen before 5.1.1 and as this problem effects both the Bose and the Sennheisers, it must be something that Apple changed in the latest update. Has anyone else experienced similar problems? Until Apple fix this, the AD2P audio streaming feature is useless. Making my AD2P devices so much useless and expensive junk.