将所有页面重定向到SAME域上的单个页面

There are versions of this question already posted but i cannot get their suggestions to work.

Here is what i have already in my htaccess

Options +FollowSymLinks 
RewriteEngine on
RewriteRule ^([A-Za-z0-9]+)$ $1.php
RewriteRule ^home\.php$ index.php 
RewriteRule ^home$ index.php

and here is what i tried:

Options +FollowSymLinks
RewriteEngine on
RewriteRule ^([A-Za-z0-9]+)$ $1.php
RewriteRule ^home\.php$ index.php 
RewriteRule ^home$ index.php
RewriteRule ^(.*)$ http://www.trainingthemlive.co.uk/maintenance.php [R=302,L]

No luck, just completely fails. I'd like www.trainingthemlive.co.uk to go to www.trainingthemlive.co.uk/maintenance

It's also worth noting that the maintenance.php page is in the root folder and def exists

You need to make sure not to redirect the maintenance page, and you probably want it before your other rules:

Options +FollowSymLinks
RewriteEngine on

RewriteRule !^/?(maintenance\.php|.*\.css|.*\.js)$ http://www.trainingthemlive.co.uk/maintenance.php [R=302,L]

RewriteRule ^([A-Za-z0-9]+)$ $1.php
RewriteRule ^home\.php$ index.php 
RewriteRule ^home$ index.php

You can use this single rule:

RewriteRule !^maintenance /maintenance [L,NC,R]

This will redirect all pages on your domain to /maintenance