The Quick Scan Methodology is a diagnostic tool used to identify improvement opportunities in supply chains. It has been applied to a number of industries around the world including the; Automotive industry in Europe and USA, the Manufacturing industry in Thailand and the Dairy and Forestry industry in New Zealand. Much of the published work on the audit focuses on the data collection tools and results. The aim of this paper is to demonstrate some of the analytical tools that can provide detailed insight into the operation of the supply chain. Here we discuss a recent Quick Scan audit of the Vendor Managed Inventory activities between a grocery retailer and manufacturer of soft drinks in the UK. In this supply chain, a large amount of demand and ordering data was available. We were able to use this in a casual loop modelling and simulation study and a black box modelling investigation. Despite the real supply chain being very complex, reasonable confidence could be given to the simplified simulation and black box models of the supply chain.