Valve lock box

[soup]

Hi all My Gran is losing it (Alhzeimers)and keeps playing tunes on the radiator valves which has the effect of leaving her house (sheltered housing)freezing. Was wondering if anyone had a link to some sort of lockable box that would stop the valves being adjusted without a key. Or indeed a lockable valve (though this would involve working on corporation heating system which I am not sure I am allowed to do). Same sort of idea as :-

I need one for a raditor valve not a wall mounted thermostat.

[Roger Mills]

Just take the knobs off, and screw the gland nuts down so the the spindle can't be turned by hand. If you want them ti look pretty, put non-rotating lockshield caps on the valves.

[Dave Plowman (News)]

Do a Google on tamper proof TRV.

[EricP]

Just pull the caps off and leave the stems.

[Peter Parry]

Replace the existing valve covers either with lockshield or a spare set of covers but before fitting them carefully drill out from the inside the shaped cutout which engages the valve stem. Assemble them on the stem with a plain washer on top and they will turn without doing anything. Simply removing the covers isn't a good idea if she has dementia as it is likely she may remember something ought to be there and get distressed if it has vanished. Keep the undrilled covers to refit later.