A lot of really obvious trolling on this thread for some reason but here's some background on RN maintenance test flying from a general aircrew perspective for interest:
Post maintenance / fault diagnosis ground and airborne checks are listed in a book, let's call it a 5M. Groundcrew can do some of these checks, engines or rotors runnning. Aircrew learn how to do this (in some forces on OCU) and therefore most if not all RN aircrew (in relevant area) can complete the entire 5M which would equate to a full test of the aircraft and it's systems. I.e. a properly constituted crew can carry out the full test. This is important when there is only 1 crew available where you are operating e.g off a ship. Normally you only test the bits that need testing therefore called a partial test flight (PTF).
Every year each aircraft needs a full check of the 5M to be carried out. The relevant MTP is the only person qualified to sign off a full Maintenance Test Flight. This is only one of their duties but one of the most visible.