Moving a multisite installation to the root from a subfolder

Hi everyone.

I currently have a fully working multisite installation running WordPress 3.5.1. It’s currently in its own subfolder just above the root (www.lfct.org.uk/lfctwp).

I have run the network setup and set the site up as a subfolder network as I want any future sites to be in subfolders and *not* subdomains. I have installed the WordPress MU Domain Mapping plugin but after playing around with it, it appears as though the plugin doesn’t support domain mapping when the main WordPress site is installed in a subfolder.

So my question is this:

How do I move my main WordPress installation from a subfolder to the root?

Thanks,

James