Changing the mixer bar on shower - have combi boiler

Hi All,
My shower is leaking and I've bought a replacement - same fittings so I "simply" have to take off the old mixer bar and put the new one one!
I have a combi boiler that does the hot water for the radiators too.
I naively think I can do the following:
0) Turn the boiler off
1) Turn off the water at the stopcock
2) Turn on the hot and cold water taps until it stops.
3) Replace the mixer bar.
4) Turn on the water again
5) Turn the boiler back on

Does this sound reasonable? Do I need to worry about water pressure and the boiler? Should I just get a professional to do this?!!

Thanks for any advice.

Gary

your plan sounds reasonable, just before you take the shower off , turn on the shower to make sure the water has stopped, other than that it is straight forward.

Agree with picasso - this is the way to do it.

Big thankyou to Picasso and Dextrous for replying and giving me the confidence to proceed.

It was all over in 5 minutes!

thanks again guys.

Gary