I had a reply from Councillor Addison, Crofton Park Ward. She had just been made aware of the application.
She told me that three objections (already received) were sufficient to take it to planning committee rather than the decision being made by officers.
She also said that, if there are 10 objections (individual ones rather than names on a petition) then there will have to be a public meeting, which would be a good opportunity to gather information from the applicant.