iOS 6.1.3 - Battery drainage, WiFi & Bluetooth

After upgrading to iOS 6.1.3 on iPhone 4s I am experiencing a severe battery drainage & greyed out WiFi button. Similarly the battery drainage happened on a previous upgrade during the iOS 5 period which after subsequent updates appeared to fix itself. Is the same thing happening again with the new upgrade? iOS 6.1.3 appears to have affected the battery drainage and WiFi. A previous upgrade iOS 6 saw the bluetooth unable to connect to my BlueAnt Bluetooth in-car device. Surely these three things are not coincidental? Or are they? I have done a hard restart (is that the correct terminology) by holding down the power and main button simultaneously and this did not change anything. I tbacked up the phone and restored to factory settings and then restored the phone from the backup (info I found on an Apple forum). I have turned off Siri, location, push notifications and any apps that can access the internet and there has been no change in battery life draining. I can actually sit and watch it drain away. I was hoping to downgrade back to previous version of iOS where at least the battery life and WiFi weren't impacted and figured I could live without bluetooth for a while if I could at least have the other two functions back however have been reading that it is not possible to do so. I'm afraid I am not sure what is happening; any advice or suggestions would be welcome. Thanks in advance 😕