Parties often include a precedence clause in contracts to make sure that, in the case of discrepancies between the various documents which comprise the contract, the contract can be interpreted to resolve the discrepancy.
Akenhead J looked at just such a clause recently in relation to an NEC3 Engineering and Construction Contract, where the Contract Data Part One was said to take precedence over the Works Information. He remarked that the order of precedence clause in the contract was not the first place to look to understand a contract's meaning. The contract should be "construed in the usual way by reference to all the documents forming part of the Contract. It is only if there is an ambiguity or discrepancy between two or more contract documents that one needs to have regard" to the order of precedence clause.
So beware of assuming a document higher up the order of precedence will necessarily apply instead of other documents which form the contract. If your contract is similar to the one in this case, and the documents can be read together, then the order of precedence clause may not assist.
RWE Npower Renewables Limited v JN Bentley Limited  EWHC 978