LG Sound Bar auto-on no longer working since adjusting 360 audio settings

I adjusted the settings in my 360 box to link the Virgin remote to control the sound on TV. However, since then the sound bar no longer turns on automatically when the TV is turned on - as it used to. It does, however, turn off when both the TV and Virgin box are turned off.

I have an LG TV and an LG soundbar using the optical connection straight from the TV to the soundbar. All worked perfectly for many years until I upgraded to 360 and used the 360 box audio settings to link the TV sound to the 360 remote. I've tried to revert but nothing I do seems to resolve this. I have to turn on the sound bar with it's own remote every time I turn in the TV/Virgin box. This defeats the promise of "only one remote to control all devices".

Any ideas anyone please?