On the off-chance, I emailed the supplier in China first mentioning the problems I had encountered with the original ‘phone. To my – pleasant – surprise they offered to replace it. I had told them how long ago I had bought it and they were fine with that. They asked me to post it to them by regular airmail – which saved me quite a bit (it only cost £7) – and then to email them a proof of posting. I did this and they duly dispatched a replacement unit which arrived today and is now charging on my desk.