Rectification Deed for mistake in boundaries of a flat
I am looking to purchase a flat on 6th floor from an existing owner in a completed apartment. However, there is a mistake in the boundaries of the flat in the sale deed between the existing owner and the builder. The boundaries are show as 'Open to Sky' for North, East and West and 'Corridor' for South. Actually, the lift corridor is in East direction and rest are Open to Sky. What is the suitable option for rectification in this situation?
1) Ask the existing owner to rectify the mistake? It is doubtful if the builder will come forward for this since the project is already completed and handed over.
2) I execute a new sale deed with the existing owner and the boundaries as in the current sale deed and thereafter execute for a rectification deed along with the seller? Is this allowed or am I at fault for executing a sale deed fully knowing that the boundaries are wrong?
3) Leave the boundaries as is and continue with a new sale deed without any rectification. As this is a flat in a gated community with flat number clearly mentioned, is this a big worry at all if I want to sell it in the future?
Thankful for your advice,