@peanutcm UK midwife here. Boil the kettle for each bottle and allow to cool for 20-30 mins (gives a temp of around 70C). Then make up bottle, and cool bottle as a whole. That’s our advice.
Things such as the above is why we don’t recommend Prep Machines that add a cold shot, or making up...
@adkchappy I do the same job in the UK and had two losses before having my son. Some days, it’s just impossible. Sending you a gentle hug, I hope this is the cycle for you!