15% Off All Isabella Oliver Maternity Dresses 3rd June 2014 The Isabella Oliver Allegra Maternity Dress Don’t miss out! Enjoy 15% off ALL Dresses at Isabella oliver. Simply quote DRS64 at checkout. Shop Now! This week only, ends June 9 2014. Our favorite Isabella Oliver dress is one that’s perfect for your Babymoon, the Allegra Maternity Dress. The dress comes in two colors : Green and French Navy.