I have just changed the DNS entries for UKGPL.com to point to the new site. It will take a few days for the change to propagate; you will know when it has, because the site will look very different.
The old site has been migrated over and can be accessed via the "Old Site" link in the navigation menu on the left.
Any bookmarks to the old site should still work; eventually there will be some redirects in place to send such links to their new homes.
The data on the new site is not fully migrated, so don't be alarmed if races and so on are missing. They are coming.
Please report any unexpected wierdness here.