Control Panel URLs being rewritten to use index.php?p=admin/ All of our control panel URLs are being rewritten to show index.php?p=admin/***

While this isn't a problem in itself we can't determine why it's happening when the frontend of the website itself is writing the URLs cleanly and correctly without the index.php?p= 

We have in our .htaccess file

&lt;IfModule mod_rewrite.c&gt;
  RewriteEngine On

  # Send would-be 404 requests to Craft
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_URI} !^/(favicon\.ico|apple-touch-icon.*\.png)$ [NC]
  RewriteRule (.+) index.php?p=$1 [QSA,L]
&lt;/IfModule&gt;


There are no other Rewrites happening.

A possibly related issue we're seeing is that there are no entries, assets or categories listing in the control panel. Looking through the logs I can see the following

2015/09/22 16:55:23 [error] [exception.Craft\HttpException.400] exception 'Craft\HttpException' with message 'Param “elementType” doesn’t exist.' in /var/www/vhosts/mysite.org/httpdocs/craft/app/services/HttpRequestService.php:586
Stack trace:
#0 /var/www/vhosts/mysite.org/httpdocs/craft/app/controllers/BaseElementsController.php(50): Craft\HttpRequestService-&gt;getRequiredParam('elementType')
#1 /var/www/vhosts/mysite.org/httpdocs/craft/app/controllers/ElementIndexController.php(68): Craft\BaseElementsController-&gt;getElementType()
#2 /var/www/vhosts/mysite.org/httpdocs/craft/app/framework/web/CWebApplication.php(281): Craft\ElementIndexController-&gt;init()
#3 /var/www/vhosts/mysite.org/httpdocs/craft/app/etc/web/WebApp.php(784): CWebApplication-&gt;runController('elementIndex/ge...')
#4 /var/www/vhosts/mysite.org/httpdocs/craft/app/etc/web/WebApp.php(276): Craft\WebApp-&gt;_processActionRequest()
#5 /var/www/vhosts/mysite.org/httpdocs/craft/app/framework/base/CApplication.php(184): Craft\WebApp-&gt;processRequest()
#6 /var/www/vhosts/mysite.org/httpdocs/craft/app/index.php(62): CApplication-&gt;run()
#7 /var/www/vhosts/mysite.org/httpdocs/index.php(40): require_once('/var/www/vhosts...')
#8 {main}
REQUEST_URI=/index.php?p=admin/actions/elementIndex/getElements
HTTP_REFERER=http://mysite.org/index.php?p=admin/entries/pages
---
2015/09/22 16:55:23 [error] [application] Param “elementType” doesn’t exist.

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We do have PATH_INFO installed and enabled on the server.

Craft Pro 2.4.2692

Any help would be much appreciated.
Many thanks
With regard to the 2nd part of the original question, whereby no entry, asset, category or user lists were display, this turned out to be a post_max_size issue in the php.ini config. It had been incorrectly set to 64MB rather than 64M.