failed lockout on Marzocchi forks

I'm currently running a set of Marzocchi Marathon LR forks on my Cube frame. They've got a standard lockout on them, which recently seems to have failed. They've only been used about a dozen times, and seemed to degrade over a short period; at first they would work after "pumping" the forks, but this has now failed to work as well. Has anyone any ideas for sorting these forks ? they are 2011 models but can't find any information about servicing them anywhere...and being based near Liverpool I'm also struggling to find anywhere local i could take them to for warranty repair!