Hey there!
I am a native Portuguese speaker, and in spite of being new to this website, I have considerable past experience in translation elsewhere. I can refer you to it, should you be interested. My past work has included website translations, so this type of project is something that I'm used to.
I have taken both the First Certificate in English (FCE) and Certificate in Advanced English (CAE) exams from the University of Cambridge, and achieved grade A in both of them, which corresponds to a C2 grade in the Common European Framework of Reference for Languages. This level equivalent to that of a native speaker, which leads me into thinking that I might be the person you are looking for for this job.
If you have any questions, please do ask them.
I look forward to working with you,
João F.