This extension integrates Royal Mail Shipping API V2 with Magento Shipping process. Easily create shipment and print shipping labels from magento interface. Sellers can manage shipping rates using rate matrix with complex weight and destination criteria as well. Manifest and customer collection receipt is also managed from magento.
You can download this extension from https://marketplace.magento.com/streammarket-royal-mail-shipping-manager.html
M2 version : https://extensions.streammarket.co.uk/royal-mail-shipping-manager-m2.html