Bolero / Bluetooth Hands Free Issue

Hi

I have a 2013 1.6TDi Octavia SE 5E which has been paired with a Vodafone Smart Ultra 6 and Bolero unit. It has been working flawlessly until a a few months ago. It started to have pairing issues but would sort itself out, occasionally I'd reboot the phone and turn of the ignition, etc. 

My phone and Bolero unit will currently not recognise each other. I've deleted the paired settings on both devices, done a hard reset of the phone, etc. Still won't pair. The Bolero screen advises on Device Search,  'Searching for devices... Bluetooth audio stopped. Please check the Bluetooth function and visibility are enabled on your mobile Bluetooth device (mobile telephone, audio player, etc).'

Has anyone had a similar experience? Advice would be gratefully received.

Simon