I know this might be a little late, but you can go to a seamstress and ask her to make a dress for you. You can pick out a fabric and then ask her to help you draw a sketch of what it should roughly look like

Have you googled Dancewear Shops around your area? Because almost all dance shops I go to will have at least a small section of "popular costumes" including the floaty lyrical dress.

Additionally, "Age 12" isn't a size, and clothing comes in sizes...if you are really hoping to get a dress from DDN you'll need to give proper sizes that you are looking for.

Thankyou, for advice. She got a dress fom dance direct ,just plain black. Not really what we was after but it looked lovely! x