Topshop is running into delays with its SoHo flagship and is now eyeing a November opening, instead of mid-October as originally hoped.

The New York store, Topshop’s first in the U.S. and highly anticipated considering the retailer’s reputation in Europe as a mecca for fast fashion, is racing to launch in time for holiday selling.

But as a precursor in order to ease anxious American shoppers, the U.K.-based chain will launch a U.S.-dollar version of its Web site on Sept. 9. The Web site debut coincides with the global launch of Topshop’s fall Kate Moss collection, the model’s seventh for the store.

Topshop is offering a free Kate Moss...