bbPress.org

ok, so

create a directory on your theme called ‘bbpress’
ie wp-content/themes/%your-theme-name%/bbpress

where %your-theme-name% is the name of your theme

find
wp-content/plugins/bbpress/templates/default/bbpress/user-details.php
Make a copy of this file, and put in in the directory called bbpress that you created above, so you end up with
wp-content/themes/%your-theme-name%/bbpress/user-details.php

bbPress will now use this template instead of the original

Now edit that file so that you add a new line between line 16 & 17 which currently read

<div id="bbp-single-user-details">
<div id="bbp-user-avatar">

so add

<h1>  <?php bbp_displayed_user_field( 'display_name' ); ?> </h1>

after this line so that you end up with

<div id="bbp-single-user-details">
	<h1>  <?php bbp_displayed_user_field( 'display_name' ); ?> </h1>
	<div id="bbp-user-avatar">

as the three lines.

and save

It should now display