You're on the generic UK firmware, so you should have been notified about the update. If not, you've probably done something which has removed the mp-fremantle-203-pr package. The simplest option is to reflash with the latest firmware. Your other option is to do "apt-get install mp-fremantle-203-pr" as root in X Terminal - this will pull in the whole PR1.2 update though, so you'll probably also need to tell apt-get to store the temporary files elsewhere (otherwise you'll run out of rootfs space). Unfortunately I can't recall the command-line option you need for that, but a search of the apt-get manual page should tell you.