Although I will give a little tip, we filled our bottles up in the morning and chucked them in the fridge - but only put the amount of cooled water that you needed to cool it to a perfect temp when boiling water was added - ITMS? So, when DD2 was on 200ml of formula, we would put 135mls of water in first, chuck it in the fridge, then when it was time for a feed, the water was cold, so we added 65ml of boiling water, which made the water the perfect temp for drinking - nice and warm. Then we added the formula, shook it up and there you go - a quick and easy way to prepare a bottle at the perfect temp without needing to heat it up in a jug of water beforehand
Mel, that's exactly what I do! Very easy peasy...