iPhone 5, IOS 8.1.3 - Bluetooth Weirdness

I've recently upgraded my iPhone 5S to IOS 8.1.3 and this appears to be when my bluetooth problems began!

My Plantronics bluetooth headset is nearly five years old and has previously worked with this iPhone 5 and my old 4S.

I can pair the headset and iphone just fine and even use it - so what's the problem?

Well there are two really, firstly even after pairing the iphone bluetooth continues searching, the "Devices" wheel perpetually rotates and the iphone keeps looking for bluetooth devices to connect to and this appears to reduce battery standby time.

Secondly and more annoying, if I turn my connected bluetooth device off or the bluetooth on the iphone off, I can't get them to re-connect. The iphone lists the device, but shows it as "Not connected". If I try to manually connect them, I get the "Connection unsuccessful" message - "Make sure "3XXPlantronics" is turned on and in range."

The only thing I can do is "Forget this device" and re-pair the device and iphone, which is really starting to get to me!

I've tried forgetting the device and re-booting the iphone, then re-pairing and also resetting all the network settings, but noting appears to make any difference.

Any suggestions please?

Kind regards,

Mel