C.L.
Oh boy. Well... let's just first say that flying with a child is NOT quite like flying pre-kids when you used to be able to stop and grab a handful of magazines, put on your iPod and tune out for several hours until your arrival! I also have a 9-month old and we have done one long flight with him (when he was 7 months old) and while he was SO good, he is also a very busy busy kid and actually didn't really sleep AT ALL!. Coming back, we were on a red eye, so I thought for sure he would at least sleep for most of it, but he only slept three hours and that was it! At home, he is like your LO - goes to bed at 7 and wakes up at 7 like clockwork, but on the plane, there is so much stimulation, I think it makes it hard for them to sleep.
My advice is this: just assume she won't sleep much. If she does, you're psyched and it will just mean less time to fill. But at least go with the mind frame that she won't so you won't be mentally exhausted by the realization that she's not sleeping! Go to the Dollar Store or some place like that and buy a bunch of new toys and don't bring them out until the flight. New toys are the key. If she's in to books, buy some new ones. As far as a busy book, The Tutoring Toy on Foothill has some, but they are for older kids. Our son played with a $4 set of plastic stacking cups on the plane for what seemed like forever! I highly recommend them!
Second, pack whatever kind of food/snacks you want to have. I didn't even try baby food because even here at home, we leave behind a tsunami of a mess. Luckily, my DS is still breastfed so I relied on that as well as some cheerios and crackers I put in some baggies. The flight attendants will warm bottles for you in the microwave if your LO takes them (ours unfortunately does not!).
Bring extra sets of clothes (for both you and your daughter - if she has a diaper blow-out it might be on both of you!) and an overnight diaper (or two) so you don't have to be changing her diaper all of the time. As far as sleeping, it's tough. I don't know if you plan on getting your DD her own seat (we did not), but it's pretty tough for them to get comfortable enough to sleep on you for a long duration when they are so used to sleeping in their crib. Bring any blankets or "loveys" she might need. BF her or give her a bottle when you see her getting drowsy. Close any window shades, and just hope for the best!
As far as adjusting to the time zone, this is also tough, I'm not going to lie! I'd read that the first day you're there, anything goes. Just sleep when she wants to sleep. The second day, wake her up (if she's still asleep) at her normal time (so 7 a.m. London time) and then start trying to get her to nap at her normal times. Going that direction will be easier than coming home. Coming back, you'll probably have early wake-ups (like 2 or 3 a.m.) which are tough, because you just have to get up with them for a couple of mornings. My biggest bit of advice on early mornings like that is slowly try to stretch the time she wakes up and the time you put her down for her nap.
For example, if your daughter usually wakes at 7 and then goes two-and-a-half hours awake until a nap at 9:30, try to stretch that two-and-a-half-hour window of awake time to get her closer to her "normal" napping time. So when you get back home, if she wakes at 3 a.m. that first morning (which would be 10 a.m. on London time), see if you can get her to stay awake until 6 or even 6:30 (if she's not totally melting!) before putting her down. The next day, 7:00 or 7:30, etc. I know it sounds tough, but for some reason, getting them to nap at their "normal" times helps more to get them back on track than even bed times.
But at the end of the day, you just have to relax and have a great vacation. You might be a bit more tired than you would if you were traveling without kids, but factor that in, try to nap if your DD naps, and just have a great time! When you get back home, you will get her back on schedule. Have a great time and "mind the gap"!! (A little "Underground" humor for you!)