Parliamentary Constituencies Bill

We have heard from the other side a suggestion that we should use polling districts as the building blocks, not wards, but is there not a problem with deviating from wards? Wards are agreed by an independent commission, whereas polling districts are decided based on the location of the local church hall for use as the polling station. Surely we need independent commissions that create the building blocks of wards that then form the building blocks of constituencies. The only way to do that is with the 10% or 7.5% variance.