Dear Nick Williams , thank you for posting to Community!
Since we aren't able to change the email address on your behalf, due to security reasons, if you wish to change email address, you need to create a new user name under Account > Create an Manage users.
Please follow all the required steps, and once you create a new user name, you will be able to have also the correct email address linked to your listing.
I think it’s better if you resend your message request through your Extranet inbox directly to booking.com.
Dear Nick Williams , thank you for posting to Community!
Since we aren't able to change the email address on your behalf, due to security reasons, if you wish to change email address, you need to create a new user name under Account > Create an Manage users.
Please follow all the required steps, and once you create a new user name, you will be able to have also the correct email address linked to your listing.