There were very big mistakes during the enquiry that undoubtedly hobbled the investigative process, particularly during the early phases. They include the SIO (a Detective Superintendent) not knowing powers of arrest, inadequate briefings, and the failure to investigate an anonymous letter received by the incident room. The absence of a successful prosecution was due to a combination of professional incompetence (especially revolving around command level responsibilities) and racism.
Significant progress has been made since those days IMHO – such as the use of Family Liaison Officers, guidelines as to the handling of victims and witnesses, particularly in the field of racist incidents and crimes, and ensuring that police systems provide for the pro-active use of local contacts within minority ethnic communities.