I completed the National Express survey thingy.
I got a response. The driver was well within his rights to ask Mr Pratface to turn off / use earphones on his / her device.
They are also looking to include this information in their on-board announcement prior to coaches leaving.
Well done them.
I'd go further and make all planes, coaches, buses and trains into Faraday Cages so that people can not stream or take calls. And when will people learn that just because someone is miles away, rather than just down the road, they don't have to SHOUT to be heard?