Validity of Public Notice for sale of property (TSR)

I purchased the Flat from widow of Mr A. Mr A has 3 children. The Flat was jointly owned by Mr A and his wife. After death of Mr A, the society transferred the Share Certificate in name of Mrs A (the widow). Post this, the widow sold the flat to Me. The widow did not apply for succession cert or legal heir certificate. However, as precaution the Flat agreement for sale I insisted on ALL parties ie Widow and 3 children to be part of the agreement and also published Public notice for any other legal heir claim on property. The bank also sanctioned loan basis this (loan already repaid as of today) and property tax is transferred in my name as well. Now after 5 years, I want to sale the property to another person. The new Buyer when applying for loan to the same bank is now being asked to again do a title search report (TSR) and issue public notice as the original seller who sold the property to me did not have succession certificate. My question 1. Is the bank right to insist on TSR report again for this reason 2. Isn't the property purchased in Good faith (as public notice was already given by me) bound by Statute of limitation for such legal heir claims 3.Worst case scenario, even if someone was to raise a claim as legal heir to property, what rights will he have given that the property was sold at consideration and bought in good faith. Will he be entitled to claim in property or all his claim will be limited to the consideration already paid to the original seller?