Existing & Proposed UK planning app. plans for a flat conversion

I need CAD drawings done and the DWG file supplied for existing plans of a house and the proposed plans for its conversion into multiple dwellings (flats). I have created the layout in my own 3D iPad package so I just need these put into CAD so I can use the plans and elevations for a planning application. There will likely be 1-2 revisions as its unlikely the first set of drawings will be exactly right, however having said that I do have all the required dimensions of the layout required for the new dwellings and will send all this over at the start.