The Staffordshire-based property company, which already owns a number of convenience stores under the Dave's Discount Stores brand, also purchased 23 former First Quench sites.
SEP Properties director Engrez Sanghera said the company was initially looking to rebrand all the retail stores as Bottoms Up, and then offer them as franchises.
It also planned to expand the Threshers business online, with a strong focus on wine and Champagne sales, he said.
The rights to the Wine Rack brand name had previously been bought by London-based Venus Wine and Spirits.
Commercial estate agent Christie & Co said it had received more than 3,000 offers for the 1,170 sites, and had accepted offers on 650. The remaining stores represented a "massive opportunity for regional independent operators," the company said.