EQUALITY WORKS BOTH WAYS

I am wondering if clubs are guilty of discrimination by offering different sets of prizes when a mixed team of golfers win a competition. By this I mean offering shopping vouchers (M&S or Debenhams) for ladies and pro shop vouchers for men. Often, clubs try to justify this by stating they have a poor stock of ladies’ goods in the shop, but surely this could be classed as unlawful under the Equality Act?