Apple Genius showed me how to fix this today!!!!! And it worked!
1. Back up iPhone as always (just in case)
2. Goto settings
3. Select Reset
4. Select Reset All Setting
NOTE: Your data all remains in tact, but you will need to reconfigure you iPhone (eg wallpaper, ringtone selection, mail signature etc as they will return to the defaults).
My iPhone 4S now has wifi and Bluetooth back!