Normally precon survey is done to document the existing conditions of neighboring houses so that claims which are made can be verified. Whether illegal structure or not is covered I’m not too sure. But if the structure is already there and damage is a direct result of the construction, the builder should rectify the damages.
survey is not needed unless you want to confirm encroachment and such. Even then, there’s no need to submit to URA if you are just doing an A&A.
that’s why I had advised you to find an experienced builder instead of relying on your contractor. Normally people who had not done landed houses before do not known the processes required