The podcast host, who became known by her social media handle, Bowelbabe, died on 28 June, after being diagnosed with bowel cancer in 2016. She was 40.
McFly’s Tom Fletcher and wife Giovanna were also among the attendees at St Mary’s Church in Barnes on Wednesday (20 July) afternoon.
The service saw husband Sebastien deliver a eulogy while their children Hugo and Eloise both read poems.
Family friend and classically trained jazz singer Natalie Rushdie, who is married to novelist Salman Rushdie’s son Zafar, sang “Tell Me It’s Not True” from the musical Blood Brothers.
Cellist Charles Watt played music from Gabriel Faure, while family friend Sarah Mountford read an extract from Ecclesiastes.
After the service, the family left the church for a private wake, while Deborah’s coffin was carried away by car.
Deborah, a former deputy headteacher, was diagnosed with bowel cancer in 2016 and subsequently kept her nearly one million Instagram followers up to date with her treatments.
Her candid posts about her progress and diagnosis, including videos of her dancing her way through treatment, won praise from the public and media alike.
Deborah revealed in early May that she had stopped active treatment and was seeing out her final days at her parents’ home in Woking, Surrey.
She received end-of-life care with her husband, and their two children.
In her final months, the presenter of the BBC podcast You, Me And The Big C raised almost £7 million for cancer research, with the amount climbing further following her death.
She was made a dame for her “tireless” work improving awareness of the disease, with the honour conferred by the Duke of Cambridge, who joined her family for afternoon tea and champagne at home.
William and Kate, charities, celebrities, and many whose lives have been affected by cancer shared tributes.
Additional reporting by Press Association.