The turf war among high-end Manhattan art galleries expanding to London has its latest chapter tonight. Marc Glimcher’s Pace gallery will unveil its new 9,000-square-foot London flagship space in Mayfair. After opening with an exhibition of paintings by Mark Rothko and photography by Hiroshi Sugimoto, a posh party will follow at hot new club Loulou’s, recently profiled in Vanity Fair. Further New York galleries — including David Zwirner and Michael Werner — are poised to open in their own Mayfair spaces, where Larry Gagosian already has an address. The proliferation arrives just as London art fair Frieze kicks off next week.