KD-55AG8BU 4K OLED TV. Had this for over 18 months now and although it's a great picture, using an external soundbar is essential. Unfortunately, since the May update, the sound bar connected via HDMI ARC no longer works. If I use the optical connection, it works but with no surround sound and is prone to the known fault of randomly switching the soundbar on when the TV is off. Also, I have tried the trick of disconnecting everything, reconnecting just the ARC connection and it worked until the following day then stopped again (I've tried this twice). I have now spent hours trying to sort this. Do you know if I can return the TV to John Lewis under their 5 year guarantee?
