As above. I'd recommend stopping at this point and calling an electrician to investigate the wiring properly. The red wire connected to the earth terminal is a real concern.
No it isn't, those are Ansell Oxford LED fittings
The red LED suggests the emergency light has failed its self test. Best way is to test for power at both the permanent and switched live terminals at the light.
Schneider iC60 certainly do, I don't do much domestic stuff now. I thought the Eaton domestic stuff also did but the indicator is only on the RCBOs with AFDD combined.
I don't really look for an indicator when I'm fault finding I just grab the test meter.
I had a quick look at the manual, It doesn't mention this segment lit alone. The clock must be set to operate. If the divider isn't fitted correctly etc.
-dE- is displayed on the clock part of the screen.
You will almost certainly need to set the clock before the oven will work. Does the manual mention this red indicator? Are any of the push buttons stuck which could prevent the other buttons functioning?
It is almost certainly repairable!
link 1 and 3 at the stat next then. If the pump doesn't run then there is either a fault with the pump or the wiring somewhere between the controller and pump.
If the meter is moving continually with the stop tap in the house open but stops when the stop tap in the house is closed this suggests a leak at some point after the stop tap. My father recently had a very small pinhole leak in the pipe between the stop tap at the meter in the road and the stop...
You seem to be most of the way there with fault finding. Yes you can bypass the CH part of the control unit to test, this is quick (and possibly the safest option as it doesn't rely on prodding live parts with a test meter.) Just link whatever is in the CH on terminal to live. You haven't shown...
A 3 port valve will spring return to the hot water position. If the motor is dead that is where it will stay. If you have a volt meter test for 240V between the white and blue wires of the valve when heating is on. If 240V is present there the valve motor is faulty and it needs a new motor/valve...