Private equity firm ECI Partners is mulling a sale of Britain’’ biggest off-licence drinks retailer chain, Bargain Booze, for about £90m, according to a weekend report. The firm has appointed advisers at accountancy group KPMG to carry out a strategic review, with options including a sale or refinancing of Bargain Booze. ECI took control of the business in a £64m secondary buyout from BWG in 2006. Bargain Booze now has around 640 outlets, many of them run by franchisees in the north of England. The companies were not available for comment.