iHD Red Everytime I Switch Anything On

I have no clue you know. I can’t see a boiler or heater anywhere. I rent it. 

Is there a hot water cylinder anywhere?  Sounds like an electric shower? Can you post a photo of it ?!

Ok found the hot water heater 

So that looks like it heats the water on demand, ie when you turn on any hot tap. There’s no storage tank involved. So it won’t be using electricity when you’re not at home. 
Are there timers for your three sets of under floor heating ? Maybe all controlled on the same display in your photo ⬆️ but individually selectable? 

I have the other 2 sets of underfloor heating in the bedrooms now totally switched off at the plug control to it to see if that helped but it didn’t. It’s only the main one that’s on now that covers the open plan kitchen/ living room and the bathroom 

I’m at a loss why it’s so much. I’ve moved from a 4 bed 3 reception room semi where the combined gas/elec were only £50 a month more than my electric in this flat that would fit into less than my downstairs space in my old house 

Is there a hot water cylinder anywhere?  Sounds like an electric shower? Can you post a photo of it ?!

Ok found the hot water heater 

 

I have an idea that this unit does have a small storage tank and with the control turned to maximum, it might be intermittently turning on to top up the water temperature. 
You might want to experiment with turning the control knob to the mid point (pointing straight up). If the water isn’t hot enough for you then increase the setting (turn clockwise) slightly until you get the right level. 

Do you think turning it down a bit might also stop it triggering the breaker when the shower runs for over 5 mins ? 

It’s possible .. the unit seems to be rated somewhere between 7 and 9kW so quite a power draw

Thinking about your underfloor heating… do you switch it on for the 2 hours using the thermostat control in your picture ? I wonder if it’s also switching on during the afternoon while you’re out, on a timer already set up on that controller. Is the room cold when you get home in the afternoon ?