From the Quick Start Guide, the KD65S9005 seems to be a 2014 TV.
According to this:-
https://www.sony.co.uk/electronics/televisions-speakers-speaker-grilles/swf-br100#product_details_de...
that subwoofer is only compatible with certain 2014 TV sets,
And certainly, given that much of the subwoofer control relies on the TV, and is executed through the TV menus, the TVs that support it need to know all about it, and how to drive the transceiver it uses,
Which your new 65A1 doesn't; and it has its own built-in sub, rather than relying on an external one.
Try experimenting with the 65A1 to see if you can get enough bass out of it anyway.
Or failing that, it does seem to have a sub out, but this is wired, and so will need to go to a wired sub, and your existing sub does not seem to have any audio inputs, just the wifi link used by your earlier TV.
YouView Superuser, but not an employee of YouView, nor retained by them for this purpose. It's purely me speaking
