Possibly but its a lot more intimidating for someone to change a hardwired
digital timer than a £5 plug in mechanical "thingy" plus they can't take
off
the timer just plug the heater straight into the socket.

If this is more of a security issue, perhaps a central timer in a secure
location might be more appropriate, with just a 13A thermostat/FCU at the
heating position. Unfortunately, this may involve some wiring, although that
should probably be done anyway, as you shouldn't really use a ring main for
fixed electric heating.

Just using a local programmer, the timer controls can be overridden by the
user.

Christian.