Cold water shower problem

[rosshock]

hello, his is my first time on this forum and very new to DIY. I have just purchased a house and have got a combi boiler. When using the shower the temperature of the water is extremely hot. When i run the cold alone the water pressure is fine. When i run cold and hot together through a mixer tap and out of the shower head i need to put the cold tap on full and barely put the hot tap on and the water temperature is still boiling hot

Any help would be greatly appreciated