Hey @RossJarv!
Happy to help here.
This user using the Wordpress API + Retool got unblocked after switching their body type from Binary to Raw. Not sure if it's the same issue you're facing, but could be worth a try!
https://community.retool.com/t/unable-to-call-api-invalid-content-disposition-specified/27185/8
Otherwise, have you been able to make any other successful Wordpress queries (e.g. a simple GET query to the Wordpress API) in Retool?