OP I've sent you an email.
Thought I'd post the bottle feeding info up here too as it may help others if they are searching forums for info on this in future.
We had a 33 hour trip our and then about a 55 hour trip back with an exclusively bottle fed baby who had to have powdered formula due to a milk allergy (the mini packs of liquid formula is not available for dairy free formula). On the journey back we were also weaning as well, but milk was still the main source of food.
You need to allow for delays so round up by about 10 hours and to work out how many bottles you'll need. It’s just not possible to take ALL the bottles that you’ll need for the whole trip (including delays), and sterilising a bottle on board is next to impossible. I replicated the perfect prep, our system was:
I took 2 bottles. One bottle was used for drinking, the other bottle was used for measuring.
I took a 500ml thermos flask which I filled up at a costa/starbucks at each airport (we had 3 flights in total).
I took a 750ml bottle of bottled water on board. Evian is safe for babies. Others can be too, just check the salt content.
I used a sandwich bag to line the ‘drinking’ bottle (Tesco small tie bag sandwich bag worked well).
I then emptied in the formula from our formula pots into the ‘drinking’ bottle.
We needed 6oz bottles, 3oz hot and 3oz cold got it to the right drinking temp for my baby. I poured my water from the hot water from a flask into the ‘measuring’ bottle (3 oz). I then added this to the ‘drinking’ bottle.
Repeat with the cold - I poured the cold water from a bottle of water into the ‘measuring’ bottle (3oz). I then added this to the ‘drinking’ bottle.
Shake the drinking bottle and give bottle as normal (the bag doesn’t affect it at all).
One baby was done I binned the bag (with any remaining milk in it), rinsed the teat in the sink using a little bottle of fairy and my fingers (making sure it didn’t touch anything!), and then I sterilised the teat in a little sippy cup with 140ml of cold water and 2 x mini milton sterilising tablets (the ones meant for the dummy steriliser, which takes 70ml of water).
The reason for the ‘measuring’ bottle is that once the bag is in place, the scale on the side of the bottle will be wonky.
This way the ‘drinking’ bottle always stays clean.