Walk-in Covid jabs in King's Lynn and Downham Market | Updated: 11:38, 09 April 2021 The Corn Exchange in Lynn is open this morning for walk-in Covid vaccinations for the over-50s. It is the first of a number of clinics in the next week in West Norfolk. The Corn Exchange is open today 8:30am to 3pm. The King's Lynn Corn Exchange on the Tuesday Market Place.. (45992037) On Sunday, Monday and Thursday, 9am to 2pm there is a walk-in vaccination clinic at Downham Market Town Hall in Bridge Street. On Tuesday you can go to the Inspire Centre at Lynn's Queen Elizabeth Hospital between 9am and 2pm for a jab.