Hi,
Under the heading, "You may find the following information useful" >> "Application Stages for Naturalisation" the statement at the end is a bit contradictory.
"Please note all nationality applications must be submitted by post, there is no public counter facility for receipt of applications. Applicants should enclose all supporting documents with their applications. If documents are not received one request will be issued giving 21 days to reply. Failure to reply within this time limit may lead to the application being refused."
Surely, if you use NCS then you dont need to send your application by post. As I see it, NCS is nothing but an extension of Home Office counter facility where you can submit your application in person.