Lavendar , Rosemary , Mint, Dill, Various Grasses, Ferns, Buddleia, Fountains, Small water ponds , Bird Baths, Wind Chimes , Sunflowers, Pampas Grass.
Any heavy scented plants would help the children as well as growing vegetables.

Hope this helps

I found this on "The Kids Garden" website.

Don't plant mint in the ground without a barrier all round, 18 inches deep, or it'll take over. Otherwise, agree with Hijuju's suggestions.

Thanks so much for your advice. The areas are contained within the concreted yard so think mint would be good. Do you know if mint is an all yaer round plant?

No, disappears in the winter, but does return (with a vengeance) the following spring.
Have a look at Santolina too - it's feathery and soft to touch, has a funny sort of smell and is evergreen (grey ferny foliage, yellow button flowers, also a green version). Senecio (now called Brachyglottis) is another soft to touch grey leaved evergreen hardy shrub, yellow daisy flowers in August, but quite different in appearance and to the sense of touch from Santolina. Phlomis fruticosa is known as the Jerusalem Sage - grey leaved again, yellow flowers again, evergreen again, but smells different from the previous two. Gets a little larger, but none of these are large shrubs.

here is a web site a found helpful when looking for sensory plants
http://www.bbc.co.uk/gardening/gardening_with_children/plantstotry_sensory.shtml

With the mint make sure its in a pot 12 inches across and sink the pot into the ground other wise it will spread like billio.
Plus not only that there are so many different varieties of mint its surprising how many different scents you can get.
These are just a few varieties of mint.;- chocolate , pineapple , ginger, peppermint, apple, pennyroyal is another type of mint, the list can go on.
These would be ideal for container gardening.
Thyme is another good one