Higher Geogrpahy LithosphereWatch
I can't help with your question as haven't done Higher geography, but will give you a tag over in the main Higher Geography thread in Scottish Qualifications to see if anyone there can help you
Sea defences like groynes, sea walls, rip rap are essential to know when mentioning human activity towards the coastal system, such as hard engineering. For GCSE, all you really need to know is the advantages and disadvantages of them to mention in you answer.
Hope that helps