Of foods, there's Gerber, Del Monte or Natures goodness, Beech Nut, and Nature's Own
I fed my dd only organic foods as much as I could. All of these brands have great organic lines! Gerbers even has Organics in the plastic, easy to travel with, cups now!!
As for the diapers, the "active Fit" is called Pampers Cruisers here.
Gerber and Beachnut are common baby foods. I use Pamper's Cruisers(stretchiest of the Pamper brand) but there is also Pamper's Baby Dry. If you were wondering prices or pictures try looking at Target or Walmart websites.
We used Earth's Best baby food- usually in the all natural and organics section of the supermarket now not with the regular baby food. They also make some yummy cookies- well ok not so yummy to me but my little man liked them! Have fun! And the baby care centers in Disney are run by Gerber so I would think they would be selling Gerber food in the parks. (the diapers are a no- name brand..diaper disaster last trip DH got the baby dressed as I got the other 3 ready- we get to the park and I am holding the baby and surprised at how not bulky he is feeling- then I realize he is NOT WEARING A DIAPER!! by shear luck he had stayed dry but little man had his first commando day at Disney!
Personally I prefer Gerber baby food... plus if you wash the plastic containers they work great for putting snacks in (Cheerios or Gold Fish Crackers). There is quite a bit more selections on this side of the pond. However I have yet to find anything equiv to Fairleys Rusks so if your little one like those you might want to bring some with you. My US born daughter got hooked on Rich Tea biscuits on one of my trips to the UK... they work good for carrying as snacks too.
I don't know how old your baby is but if you are using formula on your trip bring your own... it is more expensive here.
Incase you should need it Infant Tylenol (US, acetaminophen) and Calpol (UK, paracetamol) are pretty much the same thing.