I am planning on getting an engineer out to survey a house before putting in an offer on it. It comes with planning permission for a very large extension. I'm just wondering if I need to get someone else to look at it as well or will the engineer look at the planning aspects and the architects plans? The complicating factors are that we don't want the extension to be as big as the plans so we would need to change them and since they were drawn up the next-door neighbour has got planning for an extension so it may change the plans anyway because the available light has changed. Also does anyone know if I need to completely resubmit a planning application if I reduce the size of an extension and rearrange the rooms within that?