Both manufacturers and importers are required to submit quarterly statements on the MRN portal. You can only do that after you have registered successfully. On the ‘statement form,’ the categories are clearly split up into single/double mattresses, single/double toppers, and baby/children’s mattresses.
In your accounts, therefore, you should make sure you can generate a list of sales in each of the above categories. Manufacturers and importers can decide at their own discretion whether or not to show the amount of the waste management contribution on their receipts, or to state ‘legal contribution paid to MRN’ on their receipts.