There’s more on the Grauniad (for some value of ‘more’),
http://www.guardian.co.uk/uk/2012/dec/07/duchess-cambridge-hoax-call-nurse-found-dead
Scotland Yard has launched an investigation and is treating the death as “unexplained”.
In a statement, it said: “Police were called at approximately 9.25am on Friday, December 7, to a report of a woman found unconscious at an address in Weymouth Street, W1.
“London ambulance service attended and the woman was pronounced dead at the scene. Inquiries are continuing to establish the circumstances of the incident. The death is not being treated as suspicious at this stage”.
They’re also flogging the “victim of hoax nurse” angle, but as has been said here the deceased was the nurse on reception, not the one who gave out confidential information.