I am (if the weather ever permits it) getting to the end of my NPPL so perhaps I can contribute meaningfully. The written exams are the same as PPL. There is no radio navigation training required but RT is inevitably part of the learning. I operate out of class D airspace so need to communicate and sqwark with the best of them. The practical tests are the navigation test- same as for PPL. The cross country qualifier - triangular with 2 land aways. Same as PPL except I believe for the total distance but I am not sure about that bit. Then final handling test - same as PPL. So in real terms only the radio nav is different plus PPL does more insrument appreciation I believe. However whilst it is not a requirement I have been encouraged as proper airmanship to use all aids available so I do back up my map reading and DR with cross checks to DME/ADF. VOR has not been so useful up to now as EGNT VOR is long term outage - perhaps never to return? I feel VOR cross cuts require way too much head down time but it is another skill in the bag.