Consumer advocacy group Choice and its partner One Big Switch are refusing to provide details on how their "group buying" home loan scheme will provide appropriate offers to borrowers.On Thursday, Choice described itself as "just the referrer" and directed requests for details to One Big Switch, the newly formed firm arranging the "group buy".But, in an interview with Banking Day on Friday, One Big Switch co-founder Lachlan Harris refused to provide any further information on how the "group buy" would work. He suggested that all the necessary details were provided in a four-line statement on the One Big Switch website.Asked about One Big Switch's process, Harris said: "We've made it very, very clear what we're all about, so I don't really have anything further to add to that."We're happy to speak to any lender who is interested in being part of the process," he said.Asked to describe the process for lender selection, Harris simply repeated that he was "happy to speak to lenders about our processes".Asked if the processes had been discussed with Choice, he said, "I'm not going to comment on any discussions we've had with Choice, except just to say we're very confident they've all been entirely appropriate."Asked if One Big Switch would collect further information from borrowers during the process, Harris said, "We will interact with our members exactly as we've explained on the website, mate - I don't really have anything further to add to that." The One Big Switch website contains almost no information on the firm's processes for gathering information other than the four-line statement.Some industry sources suggested last week that the information gathered by broker One Big Switch - name, email address and postcode - was not enough to underpin serious negotiations.Harris would not say whether One Big Switch was acting as a broker, although its website contains a document headed "Finance Broking Agreement". He would say only that "we are a licensed credit holder and we are very confident that all our processes are in line with the conditions of that licence."Asked whether One Big Switch employed anyone with experience at a senior level in the consumer finance industry, he said: "Unfortunately… look, we have a great team, but I don't really have anything further to add to that."After Harris's comments, Choice communications director Christopher Zinn said Choice would not provide further details on how the group buying scheme would work. Potential users should "just wait and see", he said."It's a very different kind of deal, this… the negotiating power of the group creates the product."One Big Switch describes its process in these four lines:"1. You become a Big Switcher by registering with One Big Switch."2. Companies compete to make offers to the One Big Switch Group Switching Network."3. One Big Switch passes on special offers based on objective criteria such as quality products, fair terms and conditions, and a group discount."4. Registered switchers decide if a special switching offer is right for them."