Hi @Andrew_Lowe since you are using a custom domain you will need add a specific TXT record to verify SPF is aligned from AmazonSES (which is the underlying infrastructure we used to send emails).
Thanks for sharing the screenshot. I can see on the left hand side it shows “@”. That means this TXT record is connected to the root domain. You will also need another one TXT record the name is mail and the value is "v=spf1 include:amazonses.com ~all". This second TXT record will be separate and wont interfere with your main domain. You’ll notice that when you “view records” from the settings page in your dashboard the mail name is shown there as well.
I read somewhere that you shouldn’t have multiple SPF records otherwise authentication would fail and could lead to even more spam triggers.
“Having multiple SPF records will cause DNS lookup errors and make SPF authentication fail, potentially causing emails to be marked as spam.You need to merge all SPF records into a single, valid TXT record”
Could you confirm if you think I should still add this record you suggested?
Yes you should add the suggested record. Remember to use the mail name so that this SPF record is associated with the subdomain and not your root domain. That is the key difference here and why this additional SPF record is not a problem. So in this case, you are not adding multiple SPF records to the same level, they are separated by subdomain.