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Once you have your items in your bag, you can then increase the quantity by entering the desired amount in the Quantity field.
Clicking on the 'Continue securely' button on the 'My bag' screen takes you to the checkout area where you can select the correct delivery and billing address for this order. Please note that the billing address must match the details for the card that is being used. Once you have chosen the delivery method and clicked on the 'Continue' button, you will be taken through to the Payment page.