Perch Adding Unwanted Page Automatically

This is a bit of a weird bug - and perhaps there's an obvious solution, but I'm yet to find it!

I have a site running Perch: www.whitbylifeboat.org.uk

Here is the diagnostic report:

    Perch: 2.8.21, PHP: 5.5.30, MySQL: mysqlnd 5.0.11-dev - 20120503 - $Id: 15d5c781cfcad91193dceae1d2cdd127674ddb3e $, with PDO
    Server OS: Linux, cgi-fcgi
    Installed apps: content (2.8.21), assets (2.8.21), categories (2.8.21), perch_blog (4.6), perch_gallery (2.8.6)
    App runtimes: <?php $apps_list = array( 'content', 'categories', 'perch_blog', 'perch_gallery', );
    PERCH_LOGINPATH: /perch
    PERCH_PATH: /home/sites/whitbylifeboat.org.uk/public_html/perch
    PERCH_CORE: /home/sites/whitbylifeboat.org.uk/public_html/perch/core
    PERCH_RESFILEPATH: /home/sites/whitbylifeboat.org.uk/public_html/perch/resources
    Image manipulation: GD
    PHP limits: Max upload 64M, Max POST 64M, Memory: 128M, Total max file upload: 64M
    Resource folder writeable: Yes
    HTTP_HOST: www.whitbylifeboat.org.uk
    DOCUMENT_ROOT: /home/sites/whitbylifeboat.org.uk/public_html/
    REQUEST_URI: /perch/core/settings/diagnostics/
    SCRIPT_NAME: /perch/core/settings/diagnostics/index.php

The Bug

Occassionally, the site will add a new page to the pages list and navigation which has the same name as the URL of the site 'whitbylifeboat.org.uk'. There doesn't appear to be a pattern to when the additional page is created - though it may be triggered by logging into the admin system, but because it doesn't happen every time it's difficult to tell.

Has anyone else had a similar issue?

Thanks in advance of any suggestions!