http://www.wgtls.co.uk is the 'ladders' site you're referring to.
If you decide to register there, be sure to make your username the same as it is here at WGT.com
If you like to play alt-shot, you'll need to join one of their 'Guilds' (like a limited-membership CC) but there are plenty of other game options for the solo player. Takes a while to find your way around at first, but folks are more than ready to help out newbies.