Page 1 of Ouch that hurts...

So I can`t get a decent temperature out of my shower mixer. Combi boiler (Response 120) and tank fed cold water. It either is too cold (boiler doesn`t fire) or scalding hot. There is no middle ground. I don`t want to install an electric or power shower. Would it help changing the shower head that may be my next step. Even though it would look crap on nice new Bristan mixer.

Help before I burn my foot again!