The British Association for Shooting and Conservation works to support shooting in Britain. They have a short series on shotgun safety on their YouTube channel.
The Clay Pigeon Shooting Association is the go-to resource for anything relating to this sport. Discounted membership is offered to individuals in full time education, which provides access to insurance cover for shooting activities. Members also get the monthly Pull! magazine which features information on registered competitions and shooting grounds around the UK - great if you want to find somewhere to participate when at home during the holidays.
The CPSA have an ongoing YouTube series demonstrating how to hit different types of targets, check them out if you want some tips on how to improve your shooting.