@mitch2 thanks very much for the advice. I went with a short run of optical fibre between a pair of TP Link converters you linked in one of your previous posts above. My Cat6a feeding in to the first converter, and a short run of Supra Cat8 terminated in Telegartner connectors.
I suspected there was some noise coming from the Cat6a as it is plugged in to my router, which lives with the TV etc as described previously, but this new set up surpassed my expectations.
It feels like the stream to my Bluesound Node has been given a good clean on the way in 😊, everything sounds crystal clear. In comparison, I now realise the stream I was receiving was a tad grainy. I've swapped back and forth a few times, from Cat6a direct and the converters/Optic fibre/Cat8, and it's quite a significant improvement.
Thanks again, a great improvement, for relatively little expense👍😊