I'll have to have a think about who I know down there!!!
Not really anyone for little people - they're all mostly piano teachers who's students are quite heavily involved with exams, etc.

The Carnival Of The Animals is always a favourite with my kids - They can relate to the animals enough to know that the lion is loud & heavy, the tortoise is slow, and the fish (or aquarium) is fast & light.... they like 'playing' the animals, and they can identify to them.
Another one you might want to try if you don't mind the mess (!!!) - Painting to various different music - eg Berlioz' Symphony Fantastique is heavy & strong, and the William Tell Overture is quick and busy.... The kids love it, and are really good at slowing down & speeding up with the music, but it does get EXTREMELY messy!!! Lots of fun though, if you don't mind getting dirty!!! ... and its a perfect introduction to the world of classical music!

Good Luck finding someone.... PS. Oh you're so lucky on the concert grand!!!!!