<% content_for :title do %><%= @sector.title %>: <%= @subcategory.title %> - GOV.UK<% end %>
<% content_for :page_class, "specialist-sector-browse" %>

<header class="page-header group">
  <div class="full-width">
    <h1><span><%= @sector.title %></span> <%= @subcategory.title %></h1>
  </div>
</header>

<div class="browse-container full-width">
  <% if @subcategory.details.description.present? %>
    <div class="category-description">
      <p><%= @subcategory.details.description %></p>
    </div>
  <% end %>

  <nav class="index-list">
    <h1>A-Z</h1>
    <ul>
      <% @results.each do |content| %>
        <li>
        <h2><a href="<%= content.web_url %>"><%= content.title %></a></h2>
        </li>
      <% end %>
    </ul>
  </nav>
</div>

<div id="report-a-problem"></div>

<% content_for :title do %><%= @sector.title %>: <%= @subcategory.title %> - GOV.UK<% end %>
<% content_for :page_class, "specialist-sector-browse" %>

<header class="page-header group">
  <div class="full-width">
    <h1><span><%= @sector.title %></span> <%= @subcategory.title %></h1>
  </div>
</header>

<div class="browse-container full-width">
  <% if @subcategory.details.description.present? %>
    <div class="category-description">
      <p><%= @subcategory.details.description %></p>
    </div>
  <% end %>

  <nav class="index-list">
    <h1>A to Z</h1>
    <ul>
      <% @results.each do |content| %>
        <li>
        <h2><a href="<%= content.web_url %>"><%= content.title %></a></h2>
        </li>
      <% end %>
    </ul>
  </nav>
</div>

<div id="report-a-problem"></div>

Change "A-Z" to "A to Z"
Change "A-Z" to "A to Z"

This is in keeping with the convention in the styleguide. 
https://www.gov.uk/design-principles/style-guide/a-z