During an inquest into the death earlier this year the Oxleas NHS Foundation Trust, which oversees Green Parks House, said Mrs Mager's death "could not have been predicted or prevented".
But after court proceedings were served, the Trust admitted liability, saying they should have prevented her death.
More top news
The robbery is being connected to a spate of thefts in south east London.
Workers at two rail companies in the South East are to stage two 24-hour strikes
Eight cases of fraud and four possible thefts are being investigated, Scotland Yard said.