The service was originally to be held at 11am, but has been moved to the afternoon to accommodate friends travelling a long distance. It will be led by Torrance's friend, the Reverend Andrew Downes.
The service is intended as a celebration of Torrance's life, as well as marking his passing, and three of his close friends, Rob Whistlecroft, Martin Cass and Jeff Willis, will speak about him.
The nearest Tube to the church is Turnham Green, a 15-minute walk from the church.
After the service, friends will be invited for refreshments at Linden House, five minutes' walk from the church, and there will be an opportunity for people to share memories of Torrance, with stories and photographs.
Organisers have set up an email address at email@example.com to receive photographs illustrating Torrance's life. Those sending should include a short description and date of the image.
There is also a Just Giving page to support Torrance's favoured charity, the Richard Thomas Leukaemia fund, at www.justgiving.com/rtlf
Torrance died suddenly of a heart attack in April at the age 48 while on holiday in Thailand.
Described as a "media man", Torrance had worked for LBC Radio and Express Newspapers, before joining Adazzle, a specialist software and technology consultancy, in 2007.
He leaves behind a father, two brothers and a sister.