How do you make your formula bottles

Had my baby boy a week ago, I’d be Interested to know how you guys make up your formula bottles, we have a water filter on our kitchen tap (no different to the filter on our Tommee yippee prep machine) but we have been doing cold filtered water, adding the formula and then placing them in the fridge to heat up in the microwave as and when we need them.. fridge bottles then are used within 12 hours of them being made Just had the health visitor round who has told me this is not okay and the only way to make a formula bottle is to boil the kettle water and add the formula to this (boiling f hot) then sit to cool in a cold water bowl? As you can imagine doing this with a screaming baby seems ridiculous? How do you make up your bottles?