My hot water is to hot, we don't have a combi boiler. And the water is heated indirectly.
When I put the hot water on the water gets hot. When I put just the heating on both the radiators and the hot water gets very hot.
Can someone help me please as I am scared that some child will get burnt and my next gas bill lol

Hi... There should be a little box almost like an electric box on the outside of your water heater. There should be a little hole big enough for a screw driver with numbers that go up and down. That is the temperature for the water. The lower you put it the lower the temperature is. Use a screwdriver to turn it to a comfortable temperature. A "Kid Safe" temperature I think would be about 115 degrees.

Many codes require a mixing valve on combination boilers. How old is your unit and how good are the code requirements in you county.

I agree. I wouldn't have one without a thermostatic mixing valve for safety...