Sale of Goods Act 1979 Section 14 - Goods must be of a merchantable quality.
Said in a loud voice in shop usually gets results.
Sale of Goods Act 1979
(1) Except as provided by this section and section 15 below and subject to any other enactment, there is no implied [F11
term] about the quality or fitness for any particular purpose of goods supplied under a contract of sale.
(2)Where the seller sells goods in the course of a business, there is an implied term that the goods supplied under the contract are of satisfactory quality.
(2A)For the purposes of this Act, goods are of satisfactory quality if they meet the standard that a reasonable person would regard as satisfactory, taking account of any description of the goods, the price (if relevant) and all the other relevant circumstances.
(2B)For the purposes of this Act, the quality of goods includes their state and condition and the following (among others) are in appropriate cases aspects of the quality of goods—
(a)fitness for all the purposes for which goods of the kind in question are commonly supplied,
(b)appearance and finish,
(c)freedom from minor defects,
(2C)The term implied by subsection (2) above does not extend to any matter making the quality of goods unsatisfactory—
(a)which is specifically drawn to the buyer’s attention before the contract is made,
(b)where the buyer examines the goods before the contract is made, which that examination ought to reveal, or
(c)in the case of a contract for sale by sample, which would have been apparent on a reasonable examination of the sample.]
(2C)(b) is what they are trying on stating you should have known the shoes would let in water whilst you were examining them in a dry shop but you've got the rest of the Act on your side.