Intro to Part 102
Whereas Part 101 provides all the rules for safely operating your unmanned aircraft, Part 102 details the certification requirements for you to obtain an Unmanned Aircraft Operator Certificate. You will need a certificate if you require a variation to any of the Part 101 Rules such as operating unshielded at night, or with an aircraft that weights more than 25 kg.
Part 102 is assessed on the risk of the operations you wll be conducting. To operate under a variation to Part 101, you will need to show how you can manage the risks associated with that particular activity. You will be required to provide CAA with a series of operating manuals as part of an Exposition showing how you have identified the hazards and risks of your operation, and the ways you will mitigate those risks. Each application is considered on its merit - this allows for the wide scope of operations made possible by this technology.
Having determined that you need to be certificated for your type of operation, we have provided some documents to help you. As well as a Part 101 Compliance Matrix, there is also one for Part 102 - both need to be completed when applying for a Part 102 certificate. There's also a sample exposition that you can use as a template for your exposition.