**Rectification of the Accounting Entry**

To rectify the accounting entry for the insurance claim received, the following steps need to be taken:

1. **Identify the Incorrect Entry:**
- The incorrect entry was made when the proprietor deposited the insurance claim cheque into his private bank account.
- This resulted in the full value of the invoice being passed through the purchase book, which is not correct.

2. **Correct the Bank Account Entry:**
- The insurance claim cheque should not have been deposited into the proprietor's private bank account.
- Instead, it should have been deposited into a separate bank account specifically designated for business transactions.

3. **Create a New Bank Account Entry:**
- To rectify the entry, a new bank account entry needs to be created in the business's books.
- The insurance claim cheque amount, i.e., RS 1250, should be recorded as a credit entry in this new bank account.

4. **Reverse the Incorrect Purchase Entry:**
- The full value of the invoice should not have been passed through the purchase book.
- To rectify this, the incorrect purchase entry needs to be reversed.
- A debit entry should be made in the purchase book for the exact amount of the insurance claim, i.e., RS 1250.

5. **Record the Insurance Claim:**
- The insurance claim amount should be correctly recorded in the books of accounts.
- A credit entry should be made in the insurance account for RS 1250 to reflect the insurance claim received.

6. **Reconcile the Accounts:**
- After making the necessary rectifications, the bank account, purchase book, and insurance account need to be reconciled to ensure the correct representation of the transactions.

By following the above steps, the incorrect accounting entry made by the proprietor can be rectified, ensuring that the insurance claim is accurately recorded and the purchase book reflects the correct value of the invoice. It is important to maintain proper accounting practices to ensure accurate financial reporting and compliance with accounting standards.