A professional SEO Consulting is not bound to a specific Content Management System (CMS). An SEO consultant does not need access to the system you are using to analyze your website. Via Google Analytics and a look at the metadata of your site, he already receives relevant data. From this, first measures for you can be concluded and targeted advice can be given. A primary CMS, which is particularly well suited for SEO Consulting, also does not exist. Competent SEO consulting agencies can help you, no matter which system you use.