Slightly over 6 months or slightly under 6 months? It may well be worth referencing the Consumer Rights Act 2015, if the fault was discovered within 6 months of you taking ownership then it is presumed to have been there since the start unless the dealer can prove otherwise. If that's the case, the goods aren't of satisfactory quality and the dealer should replace the hose. The warranty with VW (a third party to the contract in this case) is pretty much irrelevant, it doesn't free the dealer of their obligations. Of course, IANAL.