@David > The most recent firmware available from Japan is 2.20, and I'm not sure what changes were made to 2.30 -- it could just be a number update for tracking a change to hardware, but as there's no info available on the UK site, I'm not sure. You could try it, unless you have a power-outage during the update which would brick the unit.
But as the old saying goes ... if it ain't broke, don't fix it. ;)