LONDON DIGS: Fifi Chachnil, known for her girly, retro-inspired lingerie creations, is headed to London. The French designer revealed she’s due to open a store there Dec. 12 on Beauchamp Place in South Kensington, in a former shoe shop. The brand was previously distributed by Agent Provocateur for 15 years. “This will help strengthen our image. It’s a lovely road with shops selling old hats and cocktail dress,” said Chachnil, who plans to throw a store-warming bash in January.