Remove "via" from emails sent to Gmail from Amazon SES
Solution 1:
Once DKIM was setup (for help, see this guide) and verified successfully on my domain I still had to enable it in the AWS console at SES -> Domains -> DKIM
Once that was done mails to Gmail no longer show up with the via bounces address.
You can see it still shows as mailed by: amazonses.com
when you view details of the sender but that's OK since it's true.
Importantly, it shows as signed by our domain.
Hope that it's as simple as enabling DKIM for you.
Solution 2:
Along with verifying the domain and enabling DKIM on the domain, I also had to enable DKIM on the verified email address I was sending from.