Retrospective approval for sunroom

hey all,

After some advice. We need to sell at some point this year.

Around 10y back while doing renos in Sydney a dodgy builder talked us naive people into lining the back with a small sunroom extension 3*2 without approval. I see some business fb posts on it being exempt development but not in any official so I don't think it is.

Now, we are told to disclose in the sale contract but I am wondering what other options are there? is retrospective approval worth it and if anyone has experience with Bayside NSW? Seems like either we lose a few buyers or they want non approval discount or council might actually ask us to demolish and it would also break flow from house to the deck or back yard. Given the house is 100+ I don't even know what else could be an issue. Not likely given it's 3br but possible

Side question given the declaration how does title insurance work for a buyer? is that voided?