I really like the Banana Boat Powder Dri if they have that in boots - it is a really light cream that drys completely when you rub it on, so that nothing sticks to it and it isn't uncomfortable. This might sound mad, but I tend to think that when you use sun cream here when it isn't that hot, because it sometimes doesn't all absorb, it makes me feel cold as it is still sitting on your skin and seems to cool down in the wind - a bit like the feeling you get when you are wet and stand in a draught. If you get what I mean! Because the banana boat stuff dries completely, I don't get that feeling, so I guess the kids don't either.
If she has sensitive skin, we have used Boots own make that doesn't have any perfumes or colours and found that good as well.