The Mail today has an article on Boots the Chemist's interpretation of EU law and, as a result, their unwillingness to offer loyalty points on milk formula. The article says "Boots said the Infant Formula and Follow On Formula Regulations 2007 banned the promotion of infant formula 'under any circumstances' and it believed loyalty points 'could be construed as promotion and therefore a breach of the law".
Looking at the Statutory Instruments 2007 No. 2531 The Infant Formula and Follow-on Formula (England) Regulations 2007, it would appear that Boots are correct in their interpretation as this SI says "23 (1) (e) undertake any other promotional activity to induce the sale of an infant formula." The SI also says that "In accordance with section 48(4A) of the Food Safety Act 1990, the Secretary of State has had regard to relevant advice given by the Food Standards Agency." and the Mail article states that "The Food Standards Agency said it advised that loyalty schemes could break the rules."