(d)  Substantive tests for purchases and other expenses
  Calculate operating and gross margin and compare to PY  1
  Review monthly purchases and investigate unexpected difference  1
  Discuss changes in key suppliers and compare to PL  1
  Recalculate a sample of invoices  1
  Recalculate prepayments and accruals   1
  Review post year-end invoices for pre year-end liabilities  1
  Sample of cash book payments to appropriate expense account  1
  GRNs to purchase invoice to purchase day book   1
  Cut-off testing using GRNs  1
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   Restricted to  5
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