“The relationship between a Banker and a customer is that of debtor and creditor in respect of the money deposited with the Banker by the customer. This position becomes clearer when a customer asks for his money. The Bank undertakes to pay cheques of the customer drawn on his current account; thus the bank becomes a debtor for the amount, which must be paid on demand. If the amount is not paid, the customer can sue the Bank. The action will lie against the bank, not the Bank Manager.”