Hi @DomSibley,
Welcome to the Community!
If you're having difficulties linking your family's Alexa and Spotify accounts, make sure that your individual Spotify accounts aren't linked with the same Amazon account. Each one of you will need to set his Echo up with an own Amazon ID, otherwise they will all sync to the same Spotify account. You can read more about this in the Good to know section of this article.
If you're interested in using voice commands for multiple Alexa devices with different Spotify accounts, I'd recommend checking out this post and follow the steps.
Hope this info is useful. Give us a shout if you need help with anything else 🙂
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