Wharfedale WH 180 bluetooth issues?

I bought 2 of these - one for my wife and one for myself. Fitted both and functioning correctly. Now 2 days later my unit won't pair with either my phone or my wife's. Both phones pair with my wife's unit. If I bring the face from my car into my wife's both phones can pair.

This suggests a problem with the bluetooth function on my unit. Short of taking it back for a replacement, are there any other suggestions?

Thanks