Does your TV have an optical out? You may be able to work it that way. Also, you say “AV”, I assume this means HDMI?
No it has a HDMI port which is hooked up but the only other place left to connect a lead is an AV port. It looks similar to an AUX port but it's not.
TV does have an optical out port, but doesn't give any sound at all when I connect it into the soundbar. Soundbar only seems to work for me when the device, such as the PS4 or Sky box etc. is plugged directly into the soundbar.
The product you sent does look like it could still work mind.