Ok, Sonos support helped me. Seems to be a combination of a bug with Google Pixel and the fact that my assistant on my phone was actually set to Gemini not the old assistant.
Some weird bugs though, I eventually signed in on my work samsung galaxy which got the assistant option to appear, but I couldn’t actually add it as I don’t have my google account logged into the work phone.
Then on my pixel phone I changed the assistant back to the old assistant instead of gemini, went into the app settings and reset the app. Still causing issues, but I also have the app on a pixel tablet, so did the same again on the tablet.
Then the Pixel phone still wouldn’t follow through all the steps to actually finish the google assistant set up, but it worked on the pixel tablet.
So, its finally working, thanks all for your assistance.