Some people learn easily, others don't. When I did my Primary Course in 1966 (not NATS) it was sheer hard graft with many hours spent burning the midnight oil and a permanent fear of failure When we all arrived for the final exams one colleague expressed surprise - hadn't realised it was The Day. He sat down for half an hour, skimmed through the books and got 98%! Some have it; others do not. If you really want the job get ready for some hard graft unless you've got a photo-memory.