Just updating to note progress for benefit of other readers. I note the following:
Calling front matter page title and adding lead text as a front matter description and removing all ‘hard coded’ headings and text from each layout template means each is generated accurately to html index files.
Front matter:
---
layout: base
title: Talks and Conferences
description: "Some leader text here"
pagination:
enabled: true
collection: talks
permalink: /:num/
---
html / liquid:
<div class="">
{%- if page.title -%}
<h2 class="page-header">{{ page.title }}</h2>
{%- endif -%}
{%- if page.description -%}
<p class="">{{ page.description}}</p>
{%- endif -%}
</div>