Arcam can sound somewhat "analytical". Kef probably has a metal dome tweeter. I myself have QED silver cables and they can sound bright. So I can understand your system might have a bright sound to it.
Honestly I am not sure a $60 pair of cable can fix that.
But if you really have to choose a different cable, I would go to the What HiFi review page and find an affordable pair of cables that can warm up the sound. What HiFi has a lot of affordable cable reviews from across the pond.
https://www.whathifi.com/us/products/accessories/audio-interconnects-analogue
Honestly I am not sure a $60 pair of cable can fix that.
But if you really have to choose a different cable, I would go to the What HiFi review page and find an affordable pair of cables that can warm up the sound. What HiFi has a lot of affordable cable reviews from across the pond.
https://www.whathifi.com/us/products/accessories/audio-interconnects-analogue