How could Sheila Seleoane remain undiscovered for so long?

Sheila Seleoane lay dead for two and a half years before her body was found - despite repeated efforts to raise the alarm. Sheila was a 58-year-old medical secretary who died in her South London flat in August 2019.In a final report by the BBC's Harry Farley, he goes back to speak to her neighbours.Today's Martha Kearney speaks to Ian McDermott, chief executive of Peabody, the housing association which was Sheila’s landlord.