IMC Rating
The IMC Rating will allow you to fly the aircraft in or above the cloud, out of sight of the earth's surface. Although the IMC Rating is a UK-only qualification, it allows you to fly the aircraft in much worse weather conditions, and also to use landing aids at most airports.
The course consists of a minimum of 15 hours flying, with a test with an examiner at the end. There is also a ground examination to sit, but once again, with a little time spent, this should not be a problem.