Costco – Milton Keynes – Opening Hours & Store Details Costco is set on Mandeville Dr, approximately a 2.98 mile distance east of the centre of Milton Keynes, in Kingston (nearby Big Rock Climbing and Broughton Brook Linear Park). The store essentially serves people from the locales of Oakgrove, Broughton, Magna Park, Brinklow, Broughton Gate, Milton Keynes Village, Kingston and Brooklands. On this page, you’ll find open hours, address, customer rating and other information about Costco Milton Keynes.