Olivia died at the scene with her three dogs, her golden retriever, Darcy, and two golden labradors, one of which was called Lily.
The family, who recently lost their step-mother, Lucinda Riley, has said her death leaves a ‘void which can never be filled’.
Olivia had woken early to walk the dogs on the Chelsea Embankment.
Her uncle Mark Riley, 71, said he was rendered ‘completely incomprehensible’ when he was told about her death.
He added: ‘It was something that is impossible to comprehend. Nobody should have to go through that at all.
‘As an individual, you just could not hope to ever meet anybody who could be so joyful, full of life and considerate of others. She had an infectious sense of humour and was a confidante for all the family members. This void is never going to be filled apart from all the fantastic memories. She was very exceptional and was fantastic to be around.’