SQS policy is there a precedence?

From Using identity-based policies with Amazon SQS - Amazon Simple Queue Service:

Using Amazon SQS and IAM policies
There are two ways to give your users permissions to your Amazon SQS resources: using the Amazon SQS policy system and using the IAM policy system. You can use one or the other, or both. For the most part, you can achieve the same result with either one.

There is one major difference between IAM and Amazon SQS policies: the Amazon SQS policy system lets you grant permission to other AWS Accounts, whereas IAM doesn't.

Basically, you can use either an SQS Policy or an IAM Policy. If one of them permits the action, with neither of them Denying the action, then the action will be permitted.

When you are using the Amazon SQS console, you are most probably using an IAM permission that has been assigned to you. If it grants the necessary permission, then the SQS Policy is not required.