I recently Flight Checked the MLS system at LHR, it's the only "operational" one in the UK, but, it can't be used "in anger" and is still only a trial with BA and us being the only aircraft with the system installed and in use (i think!).
There is no UK wide installation taking place as suggested by the Wiki link and MLS is currently playing second fiddle to FMS / GPS approaches as the future of Instrument Landing Systems.
Not that there's much wrong with the modern Cat 3 ILS
