Thanks for that info Oscar, I have spoken to a few people in relation to this overlay, the general consensus is that once you are only sub-dividing for 1 dwelling (keeping existing) that it should not have any consequences. A due  diligence is only required for 3 or more….correct??. What did town planning request and I guess why did they decide a survey was required, considering they have told me it will not be any issue once I am sticking to 2 subdivisions. (allbeit was just a phone call) .