hie I wanted to know which other procedures are there for cut off besides selecting a few GRV before year end and trace to invoices and purchases ledger.
You should also trace the other way: look at close to year-end postings to the purchases account in the nominal ledger (or purchases day book) and ensure that the GRNs are dated before year end. Alao, look at the first few entries in the new year to ensure anything posted to purchases then relates to GRNs after new year. Similarly with the purchases ledger.
Analytical procedures can also be used to ensure that the GP% has not been distorted by a cut-off error.