Past sale deeds at the time of sale

It could be ascertained by.applying encumbrance certificate to the prperty which is reliable for the purchaser.

You have informed as follows: I have the last 25years' worth of sale deeds (which covers two ownership transfers during this period

Generally it is sufficient but if surrounding lands are government etc., you may require prior sale deeds also.   Only a local advocate can give you a clear opinion on studying the original survey number etc.

Registration of a conveyance deed is a simple process. No such documents are required. However, such documents could be required by the prospective buyer while availing loan from financial institutions.