Shopify add prefix to product pages title in head section

Question

I'm looking to add a prefix text to product pages on the Shopify theme "Enterprise 2.0". I done this previously on a different theme by adding this code block to theme.liquid. However the Enterprise theme seems to work a bit differently.

        {% if template == 'product' %}
  <title>Buy {{ seo_page_title }}</title>
{% else %}
  <title>{{ seo_page_title }}</title>
{% endif %}

I can't seem to find anywhere anywhere what is setting the page title tag in any of the .liquid files and the pages seem to be made up of sections.

Any pointers?

Link to example product page

        {% if template == 'product' %}
  <title>Buy {{ seo_page_title }}</title>
{% else %}
  <title>{{ seo_page_title }}</title>
{% endif %}

Was expecting "Buy " to prefix the product name in the title tag on product pages.