I still needed the phone. I sent it off for repair. The repairers came back and said it had evidence of water damage. I can tell you that that phone has not come into contact with water. However you can see problems if you use the phone in a damp environment. I my case it is likely to have been listening to BBCRadio4 using the Tune In Radio app over the internet whilst having a shower. The phone has not been “in” the shower – just in the shower room.
This is somewhat unacceptable. Phones should not be this vulnerable. For now I don’t think there is anything to be done but designs need ruggedizing for the future. I’m going to see if I can fix it myself. Stay tuned but for the moment keep your phone out of the bathroom.