How exciting your are buying a new house.
Whether is it new or somewhat older house you need to do the checks and don’t leave it to someone else. Everyday I get calls from people who have bought someone else’s problems. What I mean is the works (sheds,dwelling additions, walls removed, 2nd storeys) don’t have permits and they need to spend a large amounts of money fixing it getting permits.
If you are buying a new house get permission from the current owner to get a copy or at least view the plans from the council. Yes it may take a couple of weeks however you will know if every thing at the property has a permit and does not become your problem to fix.
Then you can buy a property with all the current permits in place.