VFR pilot I can relate to your dilemma. There is a fine line when considering what corners can be cut, any time safety protocol is compromised there is an ethical obligation that all aviation professionals have to report these types of conditions. Here in the states we are blessed with a vehicle for this type of reporting that protects the individual reporting the incident. The Aviation Safety Reporting System which utilizes NASA as a third party between the individual and the FAA; NASA receives and administers the forms allowing for anominity to the FAA and the alleged violators as to who actually reported the violation. Yet still an investigation will take place if the circumstances warrant it.My sugestion is to contact the local authorities or even an aviation attorney to look at all of your options.Be advised by not reporting you are in fact a party to the act and could be liable in the event of an Aircraft failure resulting in injuries or death.The website below may give you some guidance. Good luck.
http://asrs.arc.nasa.gov/immunity.htm#1