Environmentally friendly company

You notice a significant number of small irregular entries in the incoming and outgoing figures...

You are a part-time bookkeeper for a company which supplies ‘green’ building materials for high-spec eco-homes. Your job role includes posting financial transactions into the company’s accounting system. One of the company directors is building a new ‘environmentally- friendly’ home for himself and his family. He is supporting the company by using the materials they supply to build the house. However, you have noticed a significant number of small irregular entries in the incoming and outgoing figures, and are starting to suspect that the director could be charging purchase invoices to the company which should actually be charged to his personal account. What do you do?