If it seems the domestic water pump isn't working BTW, the filter sealine fits stays full of water and pops off when it freezes, so the pump can't suck any water in.
Personally i wouldn't leave a fan heater on for long unattended periods. i believe them to be inherently unsafe. oil filled much better
What's the panel's opinion though - should the marina staff have noticed that the power was out at the shore power control box and turned it back on? - as I've said it must have been off for over three weeks and no-one there seems to have noticed. It won't just be my boat that is affected but there were no other owners about today to compare notes with.
Although I take your point about fan heaters, it's sitting on a metal platform and the boat electrics are protected by mcb's if any faults. The heater is also set on 1kw not 2 kw so shouldn't be at any major risk.