Dorothy Perkins is having a sale - the sale items are clearly grouped (10%, 20% or 30% off).
Their dresses are quite reasonably priced - some from £15.40.
http://www.dorothyperkins.com/webapp/wcs/stores/servlet/CatalogNavigationSearchResultCmd?pageSize=20&catalogId=33053&viewAllFlag=false&langId=-1&sort_field=Relevance&beginIndex=1&categoryId=444513&storeId=12552&parent_categoryId=291042&refinements=category~[464499|444513]&noOfRefinements=1#pageSize=20&catalogId=33053&viewAllFlag=false&langId=-1&sort_field=Relevance&beginIndex=1&categoryId=444513&storeId=12552&parent_categoryId=291042&refinements=category~[464499|444513]^category~[467252|464499]&noOfRefinements=2
Sizes range from 4 - 22!
Shipping to Australia is £10.50.