You may need to be more specific. Do you have shaped beds or rectangular ?
The oem supplier was heirlooms.
Most bedding suppliers seem to buy in bedding and modify it ( the ones I have seen anyway ). If you have a shaped duvet buy on the basic size. Turn it inside out and run a sewing machine round the corners to match the duvet shape and low and behold for a few mins effort you have a custom cover using your choice of decent bedding.