Having to top up the radiator going on a run gauge running high into red chacking under bonnet I have noticed steam coming out of the pipes leading into the heater matrix how can I take out the old heater matrix to replace with a new one and would that solve the problem of losing water I have no visible leaks anywhere that I can see
Don't replace anything without just cause. It may be a fine leak that you don't see, or it may be an internal leak. Pressure testing is the best way to go after this.
The cooalnt should be a 50/50 mix. Too weak or too strong can cause problems.