hello
i have a shoot at a ballroom june 25th and desperately in need of long gowns or anything that would fit a masaqurade/ ballroom theme
in live in london UK so not sure if i can buy from over seas as it might not get to me in time!

The UK makes the best ballroom costumes in the world.  I would check every thrift store you can get too, they always have formal wear, plus costume rental shops.  Good Luck!