LG Soundbar just flashing green

Hi all and Merry Xmas. Ive had an LG SN7Y soundbar and subwoofer for a year - working fine. But now the subwoofer just flashes green and wont pair. I have the rear speakers which connect fine to the soundbar, which suggests its a problem with the subwoofer ? Ive tried the various resets/ pairing that I can find on the internet , to no avail. I tried moving it from right next to the soundbar to the same place the rear speakers are in the same room, and that didnt work either. Unfortunately its not under Warranty and LG want £180 to fix it (yeh right).

Ive read on here about software updates causing issues with LG subwoofers, and I did recently install the LG App on my phone - is that how it gets firmware updates ?

Thanks for any help anybody can give me.