Sainsbury's - barnstaple, devon - opening hours & store details sainsbury's superstore is proud to be located in roundswell retail park on gratton way, about a 1.34 mile distance south-west from the centre of barnstaple, in roundswell ( along a3125 ).. About sainsburys restaurant. sainsbury's restaurant - with fairtrade coffee, british meat and child-friendly menu options, our instore caf