The knife shown by Time Bandit is completely legitimate. I had one that was identical, BNIB given to me by an NCO in 1 Para several years back. I in turn passed it on to a young chap in our village who was joining up as a trainee officer on tanks and was doing some partime work in the local pub before he went.
These exact knives were carried in depot stores, if not now, then until at least 2010, and were available to members of the Parachute Regiment 'on request' I was told. Certainly, my NCO buddy told me that some of the guys drew them from stores and carried them during 'Operation Barras', the rescue of half a dozen Irish Rangers from Sierra Leone back in 2000.
I think 'Time Bandit' will confirm that there are no markings on the knife whatsoever, they are completely 'sterile' as has been procedure with these particular type of service issued knives for some years now.