Hi Paul,
Perhaps it is because the "Eco 7" hour has arrived !
Not all eco 7 runs from midnight to 6. e.g. (Manweb region in Wales by Scottish Power) one get off peak electricity between 2 and 5pm in the afternoon and between 10pm and 9am overnight.
Yap..tried "ungone" the fuse but it did not help (cannot even be sure that one of those lableed as storage heaters fuses is actually an immersion heater fuse). The electrician who installed it was just to 'clever' to have left everything unlabled...
Is economy 7 a completely different...
The immersion heater in my house has stopped working and I called in a plumber who simply replaces the immersion element and it is still not working. (despite assurance that he has 'tested' it).
The hot water tank has a single immersion element at the bottom which is connected to a switch on...