I must be going blind!!
I can't see the reset switch.
There are no obvious buttons or switches that I can see and I can't find a picture of one to see exactly what I should be looking for.
Scratch that. After more time googling I found out where the button is hidden.
Thanks for...
Moved into a flat with one of these water heaters and a helpful idiot turned off the top plug (the other two are labelled off peak and on peak).
When I noticed, I turned it back on, but now all I get is a red fault light and no hot water.
I phoned a plumber who told me I would have to...