Thank you for your question. You can edit the dispatch notification email templates source code and add another product to it. The item should have it's data on some website so you'd be able to refer to it.
There's source code for example email here: https://www.linnworks.com/support/emails/email-notifications/editing-email-templates/template-examples#
After a bit of editing, you could use that to add your advertising to the email.
Here's a link to documentation about editing email templates: https://www.linnworks.com/support/emails/email-notifications/editing-email-templates
And link to key concepts of email functionality in Linnworks: http://www.linnworks.com/support/emails/key-concepts
Hope this helps.
With Best Regards,
Is it possible to include other item i have in my invenrty using the email templates when sending dispatch notifications.