The Disclosure and Barring Service (DBS) website holds a lot of information that can be used to answer a number of queries, relating to DBS products and services.
Using GOV.UK will help you find an instant answer to their most common queries and the information is available 24 hours a day, seven days a week.
Before contacting them, try finding the answer to your query online. You never know, you might find the answer you need.