@Matt75: The next thing to try would be resetting the Buds. Open the Wearables app and go to About Earbuds > Reset Earbuds, then pair them with your phone once more. Has this resolved your issue? If not then I recommend visiting a Support Centre where an engineer will be able to inspect the buds for you. To find your nearest one please check the link below, select 'Mobile Device > Phones, Tablets and Wearables' and enter your post code.