wish I had know before buying

Do you play from sources other than the V6 box? If not, you could just connect the V6 optical out directly to the PlayBase.

I use an Amazon fire stick and stream through Cromecast also

Assuming you have more than one source and they all have optical out, a cheap digital optical switch (you need a switch, not a splitter) would do. I used to use one made by ViewHD and I have seen one by CYP. Otherwise you need an HDMI switch with optical out. To get the OTA TV audio out,the HDMI switch needs to support HDMI-ARC.

I use an Amazon fire stick and stream through Cromecast also
Sorry, I should have read your original post properly.

Something like this, then:
https://www.amazon.co.uk/dp/B00N2MGTTE

Thank you for your help, I just don’t understand how it works, I’m guessing I plug my optical cable directly from my play base to it, on the other end I connect my V6 box via HDMI or optical, how do I connect my tv if I plug it direct from my optical on my tv it still won’t pass 5.1,

Maybe I should just buy a new tv, I have been looking but on there description it says optical digital out on the description of new TVs does this mean it passes 5.1,

Maybe I should just buy a new tv, I have been looking but on there description it says optical digital out on the description of new TVs does this mean it passes 5.1,No it doesn't, although most now do.

Ok, so neither your Fire TV stick nor your ChromeCast have optical outputs, so the optical switch is not the correct approach.

Buying a new TV, checking that it supports 5.1 pass-through over its optical out is one option, albeit expensive and disruptive. Worth doing only if you actually want a new TV.

Alternatively, you could try an HDMI switch that includes an optical output. This would let you switch between HDMI inputs, with the audio signal split out and sent to the PlayBase. Perhaps something like [1].

The V6, Chromecast and Fire TV stick would plug into the HDMI inputs of the switch. A single HDMI output from the switch would go to a single HDMI input on your TV. The audio optical output from the switch would go to your PlayBase.

You would then need to switch HDMI inputs using the HDMI switch control, not the input selector on your TV remote.

[1] https://www.amazon.co.uk/Switcher-AudioToslink-Digital-Coaxial-Support/dp/B00DZIXIMQ

Great advice @pwt. I am not sure that particular example supports HDMI-ARC. I think it would need this if the TV's own audio were one of the sources. I'm not totally sure about that. If so then the TV would need to support ARC and so would the switch (??)

It’s so confusing