I tried the spanx on today under my dress and they really did make a difference (according to my friend)
A lot of giggling was involved in the trying on, as they are tricky to get up!!!
I'm gonna keep an eye on ebay foor a pair a little cheaper than £30... although the dress was free, so I don't really mind too much.
Thanks for all the advice guys.
Emma xXx
PS: Gymclasshero, my dress is fitted over the bust, then has a full skirt that hangs quite loosely so you shouldn't see them at all, and you couldn't today in the changing room.