Although this report refers to a specific website, the issue is much wider in that it highlights the risks of using uncertified 3rd-party NOTAM websites and electronic planning aids that might have errors or missing information. The definitive source of NOTAM information is the NATS AIS website but, in many respects, it’s not user-friendly and so this is why people use 3rd-party providers. CHIRP has engaged with NATS about this in the past, and improvements have been made in many aspects, but we are pressing them and the CAA to provide a more graphical, chart-based NOTAM and airspace change interface to make them much more user-friendly.
The bottom-line is that although some 3rd-party NOTAM providers may well provide a more functional user interface, they are not the definitive source of NOTAM information and so should be used with extreme care.