That setup worries me a lot too - it's ok saying you "padlock" the plugs, but some unknowing person can still break/saw of the lock or even change the plug thinking the appliance is 120volt. I use a 12volt system here too, but I use the old BS546 (round pin plugs rated 5Amp) as virtually no one has these in homes any more. I keep all 230volt appliances on BS1363 as it should be.
