I’ve not been repeatedly asked for my personal details by Sonos and have several Sonos accounts that I use for Home/Holiday Home/Travelling. I’ve also not (yet) seen others mention this before in the community here, but can’t you just simply filter it out to a ’spam’ folder in your email software, perhaps by a slightly ‘unique phrase’ in the message, or it’s ‘subject heading’ etc? 

You can also deselect the contact options from Sonos (if preferred) in your online Sonos profile at this link:

https://www.sonos.com/myaccount/user/profile/

Did you check the e-mails are sent by Sonos?

Yea I checked - it’s definitely Sonos. 
I don’t really want to deselect the contact details. Let’s see if Sonos comes back to me…

You can contact/chat direct to Support Staff via this link too… https://support.sonos.com/s/contact