Three men have already been convicted over Anni Dewani's death.
South African Xolile Mngeni was convicted of premeditated murder for shooting her. Prosecutors claimed he was a hitman hired by Shrien Dewani to kill his wife, which Dewani has consistently denied.
Taxi driver Zola Tongo was jailed for 18 years after he admitted his part in the killing and another accomplice, Mziwamadoda Qwabe, also pleaded guilty to murder and was handed a 25-year prison sentence.
More top news
The great-grandmother-of-seven has explained why she won't retire from her fast food job after four decades - despite the 5am shift starts.
Sunshine gives way to cloud and showers
The Metropolitan Police Federation, which set up the official JustGiving site, said it felt a "suitable amount" had been collected.